Sorry about that. I now see you have them on the desktop! I feel a little silly, sorry, was distracted by the funky colours.
Further advice: This assumes you've tested the card with a known good monitor and cable - there's no point troubleshooting with additional unknowns in the mix!
Try Control Panel\Appearance and Personalization\Display\Screen Resolution - hit advanced settings. There's 3 things that might help here - if the next window pops up shows there's a problem.
EG, if it doesn't correctly report the information on the adapter type, or states the device has a problem, then that is worth knowing] My 470 lists as an Adapter or Chip type GTX 470, with 1280 MB or Dedicated RAM. Yours should be a 480, with 1500 [or close] MB of RAM.
Also - hit Properties on that panel - this should again list a GTX 480, and report "This device is working properly"
Back out of that screen if everything looks OK - check the COLOUR BIT DEPTH - the picture does look a little like 8 bit colour to me! This is accessed via
Control Panel\Appearance and Personalization\Display\Screen Resolution\Advanced Settings\List All Modes - check you have a "True Color" mode selected, and you'll likely have the best results with the resolution that matches your screen's Res., and also 60 Hz [assuming a flat panel/LCD screen]
That's it from me - I don't have any more ideas [except to go get ready for that job interview I have today!]
@GfS, I"ll give that a try when I get home. That sounds like it would work if the only problem was the weird colours, but I'm the most worried about the white lines across the screen during loading. Good luck on your interview! Will let you know if it works.
@amuffin, I have tried it with two monitors, two cables, but only on the same slot. I figured the mobo was brand new so everything should work just fine, whereas the card is a bit old.