i plugged in the sapphire hd 5450 and it booted nicely. it wont load windows 7(Shows blue screen). but loads windows xp. it detected my new card and i installed its software. after sometime i ran devil may cry 4 and it loaded swiftly. suddenly screen become colored. windows got stuck. this happens for twice more and i removed the card. its heat sink was hot. i booted without card and it was fine. What to do?