hi i just took my new gpu gigabyte geforce gtx 750 ti and i install it to my pc i turn it on but it freez after 1 minute my psu is 550w so is not the problem and 2 weeks as far as now i was using my motherboard gpu http:// before motherboard s gpu i had have a gt 520..when i sold it i reset my bios only god know why and now when i put my new gpu it freeze but if i use my motherboards it starts normally i disable my motherboard s gpu from devise manager but the same plz help quickly