Fuzziness on a 5770

For about a week now, DVD playback on my computer can be described as fuzzy like film grain with colours melding together. Also the normal desktop screen is lighter than it should be. Especially on full screen. I've tried updating the drivers for my graphics card, down grading them. I cleaned out the hardware because it was swimming in dust and I've played around with the monitor's settings. And I've removed and changed codecs.

The Graphics card I have is a 5770 ATI card. The processor is an i5. I've tried everything short of wiping the hard drive and starting from scratch. I've also noticed that for some reason the RAM is running at 31 - 38% with nothing running...

I'm curious to know what it might be.

Is it overheating?
If green lines are dotted pixels appear on the screen then the card is faulty

Not that I can see, it's just that the screen is off colour during DVD playback, when it didn't a week ago.

I've tried updating the drivers for my graphics card, down grading them

This means the problem is not a software issue, it could be the card