Why my pc always freeze???? even fresh from formaT? hardware defect??

Is there a software or bootable file that can check all of my hardware in my motherboard if there are some defect?? please.. help..



Why my computer freezes randomly but more on while viewing webcams and with audio chatting? ?
What might be the problem?
it also freezes while idle because i live my computer downloading some file and when i come back, i cant move the mouse..

sometimes, after restart from being freeze, i cant move the mouse(its not freeze) but the keyboard is working so i must restart it again like a new mouse has been inserted.

i already spyware, malware and anti virus. and for me to be sure, i already formatted it. but while installing firefox, it freezes again.

i think i have hardware problems, but if i have a defective hardware, do you think i can boot up my pc??

what do u think is the problem???

sometimes blue screen after freezing.

any suggestions??

Additional Details


it also freezes while we dont have internet conection.

my pc:
dual core 1.8ghrz
geforce 9600gso 384mb 192bit
2.5gig ram
80gig hd

2 days ago
i have two ram modules, one 512mb ddr2 667 and 2 gig 667. i already tested both by removing 1 of them. in 512mb mb only, my pc freezes. in 2 gig , my pc also freezes. and in both , freeze again. every time i set the modules, i monitor my pc for a week. i dont think that that might me the problem.

sorry from my grammar. im not really good in english eheh...