System hanging/freezing randomly

Hi! My name is Steven, I'm a Java programmer and I make server-sided mods for Minecraft. I've been having an "infuriatingly-inconvenient" issue with my computer. Out of the blue (not bsod), my computer will just cease to respond. Let me break up the problem below.

TIMELINE OF EVENTS 1

1. Enjoying time on computer
2. Current window stops responding
3. Go to taskbar to minimize
4. Taskbar stops responding
5. Hard reset

TIMELINE OF EVENTS 2

1. Started up computer and after it's done booting, I decide to mess around on my laptop
2. Urge to play a game or do something that only my desktop can handle
3. Click start menu on desktop
4. Start menu doesn't appear
5. Taskbar stops responding
6. Desktop (dwm.exe) stops responding
7. Hard reset

TIMELINE OF EVENTS 3

1. Right-click at any time
2. explorer.exe stops responding
3. Everything stops responding
4. Hard reset

ADDITIONAL DETAILS

1. I do not get any "program.exe has stopped responding" pop-ups. I just get the loading cursor.
2. I've ran a virus scan with ASC 7.
3. My HDD is failing and I'm trying to perpetuate it for as long as I can while I buy a new one and back up my files.
4. My system will hang (or freeze, can't tell) even during system restores and chkdsk protocols.
5. Here in Arizona, it gets extremely hot in the summer, and it's the start of July at the time of this thread's creation. Not to mention, I store my tower in a little compartment with little to no ventilation, so overheating may be a big factor here. I've attached an image of what I mean.

I'm currently doing a system restore to June 25th.

Any help on this would be heavily appreciated. I know I'm asking a lot from my first thread on here but hey, I'm sure you're all an intelligent group. Thank you in advance!

Steven

Determine with certainty if its overheating by installing CoreTemp, putting its temps in the SysTray and setting Protection it to hibernate the PC if it reaches 90% of max. All vents should be clear and if overheating you need a case fan or cooler environment, keep case and heatsink clean and freshly pasted with Thermal Compound.

This step and others to check over your PC are in Troubleshooting Steps for Windows 7.

If your HD is failing you've probably already found your problem. Do the HD test in tutorial to be sure. You must have it backed up against failure or risk losing your files.

I'm in NV and know what you mean about hot weather in July.
You must have A/C running which should help the ambient temperature.
Make sure all fans operate and the grills are reasonably clean.
Put a box fan 5 to 10 feet from the front of the case and run it on low speed.
The box fan drops the ambient temp of my system 5-10F or so.
Might work for you until you can replace the HD.

Thanks a lot for the helpful advice. I've decided that my HDD is not worth the trouble. It's backed up and I'm replacing it with a 1TB HDD. I'll move the tower to a more open area and I'll keep you guys posted as I'm still awaiting for my new HDD to ship to BestBuy.

An SSD is the best Upgrade you can do, faster than a new $1000 rig without one.