thanx brother ....
but the problem is still there

. . it is newer version of VISTA i am using. . if i do wat u said . . .i still can't find USER/GROUP tab

. . i have tried through COMMAND PROMPT but no use!!!!!! simply i am not allowed to change any settings .... even time........ the main thing is that whenever i am accessing sumthing(like settings), it ask for a password but does'nt show where to type!!!!!
help !!!!