Windows features on/off error

Hello,
When I try to use the "Turn windows features on or off" function in Windows
Vista Home Premium, I get this message: "An error has occurred. Not all
of the features were successfully changed". I have tried several times on
different features, enabling or disabling the feature, always the same
error message and nothing is changed. When I bought this computer two months
ago it was working
because I disabled some of the games I knew I would never use.
I posted this in Vista general yesterday but got no response. If anyone has
heard of this problem, but doesn't know of a solution, please post back and
tell me that.
Something I just noticed, every time I try it, a restore point is created,
description of the restore point, "Install: Windows Modules Installer"