I installed my brand new HD6670 in my CPU day before yesterday.
Then I installed the drivers from the CD that came with it.
Then I downloaded the updated drivers from AMD and installed them too.
Till now everything was absolutely fine.
After that, today, I installed the "AMD Catalyst™ 11.10 Version 2 Preview Driver" and then, the whole screen turned black, except for the white objects (eg mouse pointer etc), which remained white. I immediately did a system restore.
Now everything went back to normal. I played a few games, and then turned off my PC.
After a few hours, when I switched it on, the DVI output didn't work...
So I now have to use VGA instead of that...
It happened after restart, so it seems to be a software thingy...
Thanks for reading my long post, and please help.
I just removed the DVI cable from both sides (monitor and GPU) and then after about 1 minute, re-inserted it, and VOILA! it worked!
Now I have have installed the v12.6 too...
Thanks for helping guys!