six months ago, i was gaming and my screened displayed lots of artifacts, then crashed. when i restarted it wouldnt get past the screen that says the brand of my motherboard. but i could launch into safe mode (but it still displays those artifacts), so i got a new GPU and the problem was fixed.
now, lately the computer is acting really bad. when i shut down sometimes it just restarts. wifi is slow, but every other device in the house is working normally. computer randomly locks up. and if i wake my computer from sleep, the pc runs, but the screen remains off.
phenom x4 940
SAPPHIRE Radeon HD 4870 (old)
WD Black WD6401AALS 640GB 7200rpm
BFG Tech LS SERIES LS-550 550W PSU