Windows 7 - computer shuts down at windows loading screen

ok, a month ago i upgraded my graphics card. went from dual hd 4850s in crossfire to a single hd 6870 dual fan by xfx.

about a week and a half ago my computer stops turning on. it makes it to the windows loading screen, or sometimes the motherboard screen before that and then shuts off.

i thought it was a power supply issue, so i bought a new one. long story short, i'm RMAing that back to newegg cuz its DOA, so i buy a new one from best buy tonight. its a 700watt corsair GS700.

my computer is still turning on and shutting right back off like it was. no change. if its not a power supply issue, i'm not sure where to go next

please help!!

ok, i just triple checked that everything is seated properly, all connections are connected. then i cleared the cmos with the button on the motherboard.

now the computer turns on, won't even get to the motherboard screen, then turns off. i've read somewhere in the last few minutes about possibly replacing the cmos battery on the motherboard? i'm at a loss here

Shot down, reset the CMOS with the on board jumpers, remove all but one stick of RAM, leave the one closest to the CPU. Disconnect all drives, HDDs and DVDs and see if it will boot to the BIOS. If so find where it says Load Setup Defaults or the like, choose it and F10, save changes, Yes, Enter.

If this work, power off reconnect drives and attempt to restart Windows. If it restarts, shut down and put RAM back in, one at a time.

ok, thanks! ill give it a try and let u kno

ok so i've found something interesting. i have the corsair H50 cpu cooler... i was trying to get my RAM out and one of the pipes coming from the water pump that is on the CPU is insanely hot!! so i tried turning on the computer again and keeping my fingers on the pump to feel if its working or not, and im not entirely sure, but i don't think my H50's water pump is working.

it sometimes is able to go farther/stay on longer in the start-up process after i don't mess with it for a while.

That would explain it.
Replace the pump and it should all be good.

Agreed, if you still have another CPU cooler put it on and see if the machine will start. The stock cooler will work but not for intense gaming or CPU-intensive tasks. IT can be shutting down due to over heat.Do you get any POST beep codes? If it more that a single short one, that could be a CPU fan fail warning, which in your case would be the pump failing.

no, no warning, no codes, no different beeps, but that probably cuz technically the cpu fan still works. the fan connected to the radiator of the H50 connects to the "cpu fan" on the mobo. the pump just connects to any case fan connection on the mobo and runs 100%.

but yea one of the 2 tubes coming from the pump is extremely hot and i don't feel any vibrations from the pump like there should be if its running. i'm pretty sure i'm past any kind of warranty on this thing from corsair as its probably 2 1/2 years-ish old now.

i don't have another heatsink. i did just get tax returns back, so i think i may use this as my opportunity to get a full tower case and new air-cooled heatsink.

Sounds like a good plan soldier.
As an experiment try swapping the radiator fan and pump leads. At any rate you probably shouldn't run it until you get a cooler on there, a water block ain't much cooling. No need to buy a board and CPU. <cough> Unless you want to of course.

BTW, I think Blackhawks and Apaches are nice choppers.

*update* ok so i got my new case and heatsink. the cpu overheating was definitely the problem and that is fixed. the computer stays on like it should.

***the problem now is that it gets to either the black windows loading screen with the windows logo and then the screen goes black and the computer doesnt respond, then i force shut down. or i get to the logon screen and then i log on and it goes to a black screen and the same thing happens.
however,
if i run in safe mode with networking, it boots just fine, but in safe mode of course, but it boots like it should. it will not boot normally tho.

any ideas?

i don't think its a hardware issue anymore. it seems like a software issue somewhere