I seem to have a bit of a reoccurring problem with a recent HD6770 I purchased.
I have been building a new rig over the past few weeks, I usually build by buying a few components on pay-day and slowly building up a new rig over the course of 3 months. With 1 month to go on my build I purchased a HD6770 with the intention to buy another soon to crossfire. As I still had some time before my build would be complete, I decided to give it a run in my old rig. Everything installed correctly, fitted, PCI-E cables in etc etc... However, I turn my computer on to hear everything power up correctly but I am receiving no signal from my monitor. As I have not come across this issue before I continued to go through various troubleshooting steps. It wasn't my PSU which is a new Antec HCG 750. It's not my motherboard, I flashed it to the latest BIOS correctly... everything. It's not the drivers (I did have a Nvidia 9800GT card before this but cleaned all drivers off before the 6770 went in).
After all the above points I just decided to sideline it for my new rig.
Well... today my new rig boots up fine. all lights and fans running (including on the 6770). But yet again, the same problem... Throw my old 9800GT in and oooooo look, I can see my screen!!
Does this sound like a faulty card? It seems so to me. Theres been quite a lot of problems crossed off against it and nothings changed. And by the end of it, it has now been tested on two computers. One old, one brand new.