Recently I have had trouble starting my computer, I press the power button and the fans spin for about a half second and the power LED is on in the front of my case. I have found out that I can power on my computer without the video card in it, (I get the video card error message) but once I pop it in 4 times out of 5 I can't start it. I have tried using different 6 pin connectors, the 4 pin molex to 6 pin connector, and its still the same stuff.
Here is a link to the video card I bought
Newegg.com - SAPPHIRE 100245L Radeon HD 4850 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card - Desktop Graphics / Video Cards
Newegg.com - Suggested Products
And the power supply
Newegg.com - BFG Tech BFGR650PSU 650W ATX12V V2.0 / EPS 12V SLI Ready CrossFire Ready Power Supply - Power Supplies
I can get my computer to boot sometimes, but not often. I have to mess with the power connector on my video card. I also Have not been able to game very well, getting BSOD in Oblivion and Fallout 3, I have not overclocked the video card either.