I am in no way a computer specialist or anything like this, just a fellow (ex-)sufferer. I too had problems with my computer crashing on regular basis, I couldn't watch any embedded videos on full screen and even out of full screen or when visiting advanced flash based websites I would get random freezes/crashes. Maybe up to 10 times a day, it was really annoying. I built the computer myself about 5 yrs ago (man how time flies!), using AMD Phenom II X3 720 processor on which I could unlock the 4th core and also overclock it very modestly from 2,8 to about 3,15GHz. I never had any problems with it crashing like this up until recently. I thought I would have to reinstall windows to get it right, but had no time for it. Then I happened to read this thread and saw many users suggesting it was more likely a hardware problem than software one. I didn't really believe it but anyway went into the bios and lowered the CPU/NB multiplier by one step (to about 3,05GHz) and also switched from manual CPU voltage control to automatic control as the overclock so minor anyway - and - no more crashing on flash!
Thnx guys.