Hiberanation has just disabled...

All problems started when I decided to intstll NVidia Capture driver. I found it, installed. Then, ehwn I wanted to enter in Hiberantion mode, the button in workshutdown was disabled. Of course I uninstalled driver. Nothing. Then system restore. Nothing. T
hen sfc/scannow. Nothing. Then, I have REINSTALLED WINDOWS. NOTHING. What to do? By the way, before installing sp1 hiberant was'n able, but after sp1 it turned on, and now... I'm looking forward to your answer.
P.S. I don't speak english well, as it isn't my native language.

If you have a Direct3D-based screen saver running, WindowsXP cannot enter the Hibernate state. Disable your screen saver and check if you still have this problem.