windows 2000 regedit

hi,
I recently upgraded to windows 2000 professional.(with default administrator login and no other users). The problem is when i open regedit tool from run menu or directly i cant click on the regedit application with my mouse. I can move through the registry keys using keyboard arrow keys but cant even click on the regedit window title bar. I dont remember changing any internal settings(may be accidently i have) but im sure it was working good the previous day.
No other problems are being detected , everything else is working just fine.no system hangs or errors ; its clean as a whistle. so i seriously doubt that i may have changed some internal settings.
please advice me on this.


thanking u
love
zid