pc freezings

[Volltboon]

hay guys,


my pc have permanently freezes (no bluescreens) and then i need to restart but i don't know why
i already reinstalled originally win 7 64 bit properly, took me about 6hours and they are still appearing, even if they are not appearing that much as before

the main problem that were was ID: 1031 then i resetted my BIOS and updated it, so i did with new win7, i reinstalled it but the freezes still appear, this time the "ID" is 1001 (upload of the admin windows protocol uploaded here at the bottom of thread)
i did cleaned the pc very good and looked after all cables but i dont think this is matter bc the freezes still appear
i also updated all drivers and someone who have some knowledge with software helped me to search for the right drivers


what i already tried:
testing the RAM - no problems(mem-test)
testing the HDD - (only error scan with HDTune)
system win7 64bit - reinstalled 2x sucessfully and updated
bios - resetted & updated


short discription of the problem:
i get system freezes (screen freezing,sound disappear) when i use 3-10 firefox windows and let as example buffer like 4-10 videos at the same time or when i download it happens often that i get freeze, sometimes i get freezes while only having open Firefox+skype and nothing more or watching a film on vlc/wmp


may someone help me out with this problem please ?
i'm able to speak russian,german and english via ts3 if necessary
if you wan't to talk in skype to me: Volltboon
feel free to add/pm me


greets

[Ammarez]

checked the cpu and its temp ?