random reboots without BSOD - sometimes several daily

Also, please go into BIOS and give me the reading for the +12V, +5V and +3.3V. Also, please advise me what your sata controller is set to (IDE, AHCI, Raid) and what you have your Vcore set to. If you can, please install core temp and tell me what your VID is while running Prime and what your Vcore is during Prime from CPUz. Only run 1 temp monitoring program at a time.

OK, ATX standards for your PSU is +/- 5%. It looks like your 3.3V is pretty low, it should be at least 3.135. Your ram is running at 1400 MHz with timings of 8-8-8-24. It is 1600MHz ram and the XMP values show 9-9-9-24 and 1.65V. You have a spd value of 8-8-8-22 but the frequency for those timings should be slightly under 1200MHz. I would suggest you set your ram to run by the SPD values. It should run either way but you will need to either lower the frequency at the timings you have now, or change the timings to the XMP values of 9-9-9-24 and set the frequency to 1600. But, whichever you choose to do, be certain to set the voltage manually. If you choose the 8-8-8-24 @1200 set the Dram Voltage at 1.5V. If you set the ram at 9-9-9-24 at 1600MHz, set the Dram Voltage at 1.65V. Your board should have an XMP setting which will set it for you, if you prefer. But I would still set the voltage manually.

I don't think the ram is causing the specific problem you are having, but it is running out of spec right now. I'm not sure what settings your board has, but I would check the "C" states. Make sure they are enabled if you want to use sleep. The C states have to do with sleep, but at least on my board they will affect the overclock you have.

Disabling hyperthreading, it is normal that the temps would drop 10C. As a try, unplug your computer from your UPS and plug it straight into a wall socket. The Battery Backup can cause similar problems if it starts malfunctioning. I've seen it happen several times. You can leave the hyperthreading off if you want to, but it just seems like a waste of money to me. A lot of overclockers do, mainly because of the heat reduction and the fact that in many cases it takes less vcore with it off.

If none of these suggestions work, I know you don't want to, but I would set everything to defaults until you get it stable. As you can see from the bottom of my signature, I am not averse to overclocking and am overclocked right now. But, I have done this long enough to know that unless you are stable at stock, no overclock will ever be stable. Also, when you start having issues, it is always best to go back to stock, stabilize it and start over. You already know your OC settings, so redoing them should not be difficult. Most boards allow you to save a profile so you can just go back and load that profile again. There are also a lot of other things that can cause a computer to shut down other than the ones you listed. A dead short being the most common.

It is common, especially with the cheaper PSU's that over time the capacitors get weaker and the PSU will not put out as much power as they did when new. The lower end power supplies also do not have the safety mechanisms as the quality ones and can put out a power surge when they go that will take out other components such as motherboards, CPUs and other components. That is why I always recommend to everyone building a computer to never save money on power supplies. Buy a quality power supply such as Seasonic, XFX, Corsair, Antec or a few others. The next power supply I buy will probably be a Seasonic. Of that list I just mentioned, most of those companies PSU's are built by Seasonic. All of the quality ones rarely lose power due to aging of capacitors and have safeguards built in to help stop a surge that can take out a whole computer. A PSU is the heart of your system. Everything depends on the PSU for proper voltage. Also remember that when a computer starts up, it is extremely stressful on the power supply. It is sitting there doing nothing. When you push the power button to start, Everything in the computer all of a sudden demands power from the PSU. It goes from a dead stop to 100% instantly. A weak PSU sometimes can't handle that load. But, after a few attempts it gets warmer and will be able to start. I'm not saying that is what is happening with you, but the possibility is there.

Another thing you have to remember is that your PSU depends on the UPS and not the wall current for proper current. All the power from the wall goes through the UPS and it determines how much power to send to the PSU. Also, I have been told by others who know more about UPS backups that a UPS will only put our it's rated power. So, For instance if you have a 1000W PSU running off of an 800W UPS, The ups will only allow 800W to be delivered to the PSU. That 1000W PSU will never put out 1000W because it can't. I've known of a couple of people who have had to return UPS systems because they needed a larger one to be able to properly power your system. Now, if that happens and the UPS begins to age and have power fluctuations it will put out less power than it should, and could have short periods of no power. I'm not saying, again, that is your problem but it is also a possibility. Just connecting your computer to the wall would answer that question.

Your answer to can a PSU do that is yes it can and the UPS can do the same. But in your case I would bypass the ups just for a test to check that out. if you continue to have the same problems, you have ruled that possibility out. Very simple and free test. PSU's also can do most anything. Some will blow up and some will just start to act up a little and get worse and worse until they quit and some will go out with one big surge of power.

As far as your ram goes, I prefer not to overclock my ram. Some people do it and are able to have ram that can do it and without problems. I'm not sure exactly how your chipset works, but many like mine and most AMD systems, if I raise the FSB it will also raise the frequency of the ram as well as the CPU. My chipset is much different than yours, so it will work different. I know years ago I had another system and to get my ram to run at 1600 I had to raise my FSB by 20% to get it there, which also overclocked the CPU, so a lot of voltage had to be adjust it to stabilize it. My current system, the FSB (bus speed) also will increase ram and voltage to the PCIe slots, meaning it increases the voltage to the GPU as well as the hard drives. I don't believe your system does, but it would be worth you looking into exactly what it does do, besides overclock the CPU. It is usually tied to something else. I have always said that overclocking is an art and not a science. Every component is affected with what you change in bios. So, the trick is to be able to change bios and keep every other component stable because everything you change to affect the CPU also affects other components.

As I stated before, I am an overclocker and am not adverse to overclocking, but every time I start having trouble, and you always do at times, I reset my bios to defaults and run all the tests I can to ensure it is stable at stock. Then I go back to the overclock. I do that because I know that over time components age and react different than they used to. No system will ever have a stable overclock unless it is perfectly stable at stock, period. I know I just had to do that with my system and ended up having to give my CPU more voltage than I had to do for almost a year with the same overclock. It happens. So, just because you have an overclock that has been stable for years, does not mean it will stay stable. If you are going to overclock, you will always have times you have to start over or go back in to make adjustments. Never use software to overclock, always do it through bios, with you making the changes. If you go to Overclock.net They have guides to almost every board there is. And what they say in their official guides are right on the money. But, all components are not made equal, so they can't tell you how much voltage your CPU needs, they can tell you how to set up your bios and what the voltage ranges are for every setting and will tell you how to adjust them and what they do. You have to do the testing and see what voltage everything needs. The first thing I always tell people about overclocking is, if you can not afford to replace it, don't overclock it. Accept the fact that overclocking puts stress on almost every component in the machine and will cause them to wear faster than normal. That stress can cause weaker components to fail. Everyone who are overclocking enthusiasts and serious about it will tell you that. On my system I can run Prime for hours at 5 GHz and it will not overheat and is absolutely stable. I could run 5 GHz 24/7 if I wanted to, but I don't. I run mine at 4.6Ghz 24/7 because that is fast enough, puts less strain on my system and it will run prime for 24 hours and never get over 68C, an my max is 105C. Meaning it is perfectly stable, puts reasonable stress on my system, and I don't have to worry about temps, no matter what I do with it. I can play any game and never get over 55C. That's what you should do. Find a stable, reasonable overclock and leave it there and don't put undue stress on your system and you will be fine. Just remember you will always have to make adjustments or go back to stock and start over. Components age and require different settings.

Just remember when reading reviews: 1) many of them are not very knowledgeable about PSUs and knowing how they work. 2) the overwhelming majority of the reviews are made when they first bought the PSU and installed it. If it works and the voltage seems OK then it is a good PSU. Rarely do the people you want to do reviews on any item do them. I want someone who has used the item for 3 years to do the review. Because it works when it's brand new means little. My motherboard worked fantastic when I bought it and first installed it. I have had to RMA it 5 times in the 1.5 years I have had it. It runs great now and is the best motherboard on the market for this CPU when it works right. I have 3 others running the same CPU, so I know. It will do things none of the others can even think of doing. But, having to RMA it 5 times means something. When you get ready to buy components, keep those things in mind and take them just as an indication. You can always come here and ask. There are an awful lot of good hardware people here who can give you advice. And their advice can differ even among the good ones. Some would tell you to buy an Nvidia card and others would tell you to buy a AMD card, and they will debate it. Truthfully, they are probably both right in the fact that it is a good card, but you have to take the information and make the decision. But again, there are an awful lot of excellent hardware experts here. You just ended up with me. Others may have told you different things with neither one of us wrong, just a different outlook and preferences. I overclock and like to run benchmarks and other things, so I am looking for components that are very high performance oriented. I don't care if it will last 10 years because I will build another system within 6 months usually. Someone else may not be concerned about the same things I am and want a stable stock system they can give to their kids in 10 years. They would give you different options and opinions than I would. So, just understand that, and it goes for reading reviews of components. Many times, looking at their system specs here can give you an idea about them, but not always. Some really know what they are talking about but have an HP laptop as their system, because mobility is important to them, but they have the knowledge and experience.

OK, I'm almost as close to running out of ideas as you are. But please goto https://downloadcenter.intel.com/default.aspx and run the Driver update utility.. You will have to download and install a file, but it is safe. I've done it numerous time. It will scan your computer to fin if you need driver updates they provide. Update your Lan driver if you can find a newer one. Please go back and read tour post #6, it talks about running out of memory. You have 3 GB of ram. You are running Windows 7 32 (X86). X86 can only address about 3.5-3.7 GB. Windows 7 is pretty good about handling ram, but the fact of the matter is that it probably takes about 50% of your ram just for Windows to run. If you do anything a little intensive, it does not take much to run out of ram. I'm not diagnosing your problem, just 'thinking out loud'. Your system is getting a little long in the tooth, so to speak, which does not mean there is anything wrong with it. It's a very nice and capable system. But, age wears on everything and things start to react different or go wrong. Of what I recall about your problem, we have run almost every test there is, and they all passed. There are just so many things that can go wrong with a computer. Can you check your wiring very closely and make sure there are no loose connections anywhere and that none of the wires have the insulation broken or missing. If a computer has most problems, it will usually BSOD. For one to just shut down, usually makes you think of a dead short or a bad PSU. But, you have done these before, but I'd like you to do them again.
SFC /SCANNOW Command - System File Checker
Disk Check I would like you to do option 2 and run chkdsk C: /f /r
And download and run WD Support / Downloads / SATA & SAS / WD Black Data Lifeguard Diagnostics for DOS run the short and the long test.

Try those and tell me what results you get. and by all means, please run everything at stock settings.