Honestly, i actually like windows 7. It works really well, boots really quick. I used windows 2000, xp , vista, linux and windows 7 has been very stable, and suprisingly its very compatible with all my old hardware, unlike vista, which didnt had drivers for my printers, motherboard etc. I do feel you tho, maybe is a hard ware problem, maybe its heating up? or a resistor on your motherboard blew, and its acting up, try re-seating your ram and unplugging your cables inside the computer. After you do that, save all your work and re-install windows. Is easy to bash an O/S , but its better to sit down and look at the issue, and check one by one what the issue is. If you need further help, just let me know, i can research with you, and get this problem fix.

Miguel