Boot Camp usage/brightness problems

I have installed Windows 7 in my MBP Mid-2010, and it was working great.

But recently, I've found a problem in my Boot Camp. When I dim the screen down to a mininum (to the point where the screen is not glowing anymore), and let it stay like that for a very long time, and when I come back, I can't make the screen bright again. It's just stuck there, and that means that I can't do anything with Windows. I tried to restart the computer, but it's still the same. I can't chage the brightness.

I tried reinstalling Windows 7, and it first worked out great, but when I did the same thing (leave the brightness to 0 for a very long time), I could never switch the brightness, again.

Any ways to solve this problem?