I added a new 1 TB SATA hard drive and it worked FINE for several months. But since last week the video card started crashing and recovering periodically every 1-2 minutes. I disabled the hard drive and everything returned to normal. I suspect it has to do with power supply. Although I have a decent PSU from Antec (I forgot the exact capacity but it is around 500W), I am also running a power-thirsty Gefore 9800 video card. But it could also be SOMETHING minor like an installation issue. I scoured the internet for days without any satisfaction. I hope you guys are more familiar with this issue.  Post all the specs of the PC so we can check...but i also suspect you are under-powered.
How old is this PSU anyways ? ?Based only on he info he gave, he should consider doing a RMA on the hard drive.The HDD is NOT the issue...It's a Core 2 desktop with a 4 GB RAM from Dell. It's pretty much an average 5-6 year old GAMING PC. My PSU is only 2-3 years old.  What model hard drive is it?
This could happen with a Western Digital Green 1tb drive.
If it is one of those drives there is a software fix.