Black Screen with horizontal coloured lines

Black Screen with horizontal coloured lines

I bought an MSI Twin Frozr III 7870 almost a year ago and up until today
it was running pretty smoothly. But, after having just moved I booted up
my PC and now I no longer get anything on screen ! After the Windows logo,
the login page is just black with a few horizontal lines yet the cursor
and password input box are still clearly visible.
When booting in safe mode though the video output is relatively fine,
everything is visible yet there are some horizontal red/gray-ish lines in
certain parts of the screen. If I remove the drivers and delete the device
through the device manager on Windows 7, then when I reboot normally I can
usually see at least the login screen and then the desktop, still with
those red/gray lines. It's only when I reinstall the drivers, either
through Window's automatic driver installation thing, or through
installing AMD's Catalyst suite, that I end up with my original black
screen with lines + cursor etc.
I unplugged my graphics card and used the card and used the video output
from my motherboard and it's all fine, no artefacts. I even moved my
graphics card to the other PIC-E slot and still the same problem.
Has anyone ever encountered this issue ? I checked my card for any glaring
physical degradation but I just can't see anything on the card that would
indicate failure. I first thought it might still be a driver thing, but
due to the artefacts that still remain even when there is stuff on the
screen I'm starting to think that it's my card that's faulty.
Any help/suggestions would be great, I can also give more details if
needed, thanks