What your looking at is two things.
If part of the gpu fails you will get a corrupted screen.
Or one of the ram memory chips has failed causing the display to become garbled with lines.
If the card has been overclocked in any manner it can be the cause.
You should try loading windows in safe mode, if you get a nice clean screen image. then uninstall the catalyst drivers through safe mode.
Restart and re install the video drivers in normal windows mode.
If it still fails and you have not overclocked the card in any manner simply RMA the card from where you bought it from.
It should have at least a years parts warranty on it.