i've been having some problems recently, and this is the worst it's been:
i got a Sapphire 4870HD 1GB Vapor-x Card, that wouldn't send a signal to the monitor when i turn on my system. there's a red light on the card that says "D1601 over temp protection", but the card is not even warm. it started when i got the system back from standby.
My other specs:
Phenom II 920 2.8Ghzx4 4Gb RAM Asus M4A78-E Mobo Vista home premium 64 bit. OCZ gamerxstream 600W PSU
HELP ME PLEASE!!!!
More aboutmega problem 4870hd
Is the fan working? Have you cleaned the cooler on the card? Have you tried removing the card out of the slot and reinserted the card? Is it less than 2 years old?