Pc randomly freezes; everything stops, yet the last image (whatever i was doing lastly) is there. No sound buzzing or anything but the only option is hard reset. Also bios doesn't show one of the three chasis fans. The other two goes slightly mad, for ex: they work at a rate of 3200 normally but for an infinitesimal period of time (like not even half of a second) they go 19000 or something without sudden acceleration. It first happened when i was using win7, then i upgraded to win10. Everything was perfect for about a month but then it happened again. It also freezed during formatting once, which led me to taking out the bios battery. Then i did a clean windows installation and now i'm writing because i think it will happen again. Also when i did an sfc scan once during win7 and once during win10 (the one i upgraded from win7) sfc found some corruptions yet was unable to fix them. But now, after a clean installation it says ''sfc didn't find any corrupted files''. That's about it, I would really be grateful if you could at least lead me to any direction. (Sorry if this is the wrong place to open this thread. I'm new on these kind of stuff.)
Edit: The freezing first happened when i was playing a game during win7 period, then it got really worse as it was freezing just after the desktop shows itself. During win10 (upgraded from win7 version) it freezed while i was watching a tv series. And then it freezed even during formatting. Now im using a clean installed win10 for about two weeks and nothing happened so far. Thanks in advance.
Edit: The freezing first happened when i was playing a game during win7 period, then it got really worse as it was freezing just after the desktop shows itself. During win10 (upgraded from win7 version) it freezed while i was watching a tv series. And then it freezed even during formatting. Now im using a clean installed win10 for about two weeks and nothing happened so far. Thanks in advance.