Editing HD Video BSOD

Hello, I have been using my pc to Edit HD video for a while without any problems but a week ago I was producing a 10 minute video(longer than my typical video) for Facebook while watching another video and everything went awry. The computer wouldn't start at all I was getting a continuous beeping indicating a video problem. After an hour I managed to boot from the Win7 dvd and repair after 3 tries it was successful. I checked everything in the device manager and all seemed fine so I tried the same task again and got another BSOD. It was extremely hot so I moved the pc to a cooler room. I removed the power supply Cleaned the entire system with compressed air and tried booting again. I was getting as far as the windows startup screen then freezing. Sometimes I would here a click, pause click pause click several times before seeing the post. I believe the click is the system speaker starting. I removed memory modules one at a time and after the second one the system booted. I checked everything and it was working well so I made sure my backup was current and ran it with just 2 memory modules for the past week. Today I put the third back in and it booted fine. I booted from Windiag and ran memory tests which are all fine. I am thinking that maybe It overheated becuase I need more ram/better video card. I am running intel core i7 920 @ 2.67 2.79 with 3GB of RAM Win7 64bit and ATI radeon HD4670. I know that this is a tough one but If anyone has any ideas I would be pleased to hear them.

Sean