You probably have your User Account Control turned on. That was the issue of mine. Go to "Control Panel", from there, go to "User Accounts and Family Safety", Click on "User Accounts", and in the list, there should be an option that says "Turn User Account Control On or Off". It will require a system restart. But fixed my problem perfectly.
I am running Windows Vista Home Premium, so I'm not sure if the tabs are the same in other Vista O/S, but I imagine they would be somewhat similar.