Yes thank you I downloaded CClearner and disabled CCC. Now it runs fine. I will test it more tomorrow. What does it mean though...? I cannot use CCC with my card?

Maybe Overdrive needs to be turned off?

But it's been off, I reinstalled the drivers probably 8 times tonight thus it resets to off by default

I guess you have not got new PSU yet. Some details: HD4850 is 100W card, while HD7770 is 80W card. - As for 6pinPCIe it's 75W (have to provide at least that) while 8pin PCIe provides 150W and more. - considering your new GA is more power efficient it did not place much work on your PSU at start. - Since your PSU have defective cooling and took hit few watts at start may have made difference in ability to have problem less boot. I only guess HD7770 protective electronics realized that your PSU can't provide all power and kept it at low voltage/clocks. It's very likely if you used 4pin-molex (for HDD/CDROM) conversion cable that it's on different rail in PSU and that one is not very capable. - I advise to use directly 6pin PCIe power connector which goes from PSU BTW 7770 should be about 15% faster than HD4850, your OC edition should do even better. But consider that it's 80W card at 1000/1125MHz Core/Memory. OC will raise this considerably.

card is 100% toast no amount of screwing with drivers or changing power supplys is gonna fix it

Fox: thanks for the suggestions, it makes sense now. I will try plugging it into a different cable, I never thought of that. Yes the new card works great, it almost doubled the performance in some games. I'm unbelievably happy. Who knows how overheated my 4850 has been for months or years (and I thought the performance was mediocre by default) onemoar: thanks, that's what I thought as well. Just wanted to make sure

^Oh so you have a PCI-e connection? I assumed you didn't hence my comment earlier but yeah def use it if it's there.