What's wrong with my new XFX Radeon HD 5770?

I suggest trying to reinstall drivers. Download driver sweeper, and get rid of ANYTHING that says ati, or catalyst...including catalyst download manager. Go to the AMD website and download the latest Catalyst version...ummm i think 11.2 is current. If that does not fix the issue, then you may be looking into replacing that card under warranty. But, Im about 75% sure this will work...just make sure you get rid of ALL video drivers with Driversweeper, and start with a clean slate.