PC no longer starts!

[Joshcore]

Okay, so I upgraded from onboard graphics to an X1650PRO yesterday. Installed fine; I played games for a few hours, enjoying my new card. Then my computer crashed. I simply rebooted, but half an hour later it froze. I restarted, tried playing again, but it froze once more so I turned it off and went to bed. When I tried starting it this morning, it came up with a message saying 'Windows could not be started...' and a heap of options, such as start normally, or start in safe mode etc. But I couldn't select any, because the keyboard was unresponsive as was the mouse.

So, I let it start with that option on default - but the screen simply goes black, and the whole thing reboots and goes through the same process. What's going on here?

Mobo: ECS P4S5GM/GL+
CPU: Intel P4 2.8Ghz Northwood
RAM: 1Gb Samsung DDR
GPU: HIS ATi X1650PRO
HDD: Seagate Barracuda 40Gb
Optical: Samsung CD+/-
PSU: Thermaltake 420W

[Dave21]

I think your psu is dying on you. Could you test it on another pc?

It could also be overheating?

[Cricket]

Test your hard drive with the manufacturer's diagnostic utility. You may have a dying hard drive or it's developed bad clusters in the boot sector.

Problem might also be the motherboard. ECS is very low quality and not known for longevity.

Cricket