I decided to clean the inside of my pc today. It was incrdedibly dusty. I took the video card out and blew it clean with air can. I also took the heatsink fan off cpu and cleaned it out as well. When I reassembled, the computer turned on and come up saying I must enter bios because cpu speed was incorrect. i went into bios, it was set like it has always been set. i clicked F10 and then it shut down. Now it starts, no beep and then shuts down. any ideas?

Did you clean and reapply new thermal compound to the CPU?

Good guide here:

http://www.d-a-l.com/help/general-ha...-material.html

No I did not. I thought that might be the reason. I will do that and let you know. Thanks.

I don't think thermal compound or lack of it, would prevent the computer from booting. It would cause it to over heat and shut down fairly quickly though.

I would remove and re-seat the video card again and check all other connectors to make sure you didn't knock something else loose. Check RAM seating as well. My bet is the video card though.

Thanks Rich. I applied the thermal compound and it booted right up. Everything seems to being working now. No BSOD yet. I will keep my fingers crossed. Thanks for all the help. I think it might be the vid card as well, if so I am upgrading the whole system.