It seems that if a domain exists, or possibly a workgroup, with greater
permissions in the heirarchy (meaning that your computer is merely a
workstation on a larger network), there can be functions not allowed on the
client computer. It seems that this is the problem on mine. It may be the
problem on yours as well.
I bought my computer used and didn't realize until after I bought it that
the shop I bought it from was given a user account password, not the
administrator password. Since then I have found that this computer was a
client on a larger network. The only way I can fix the problem is to
reinstall the OS from the disc. I purchased a new copy of the OS and will be
installing it soon. I suggest that if you have the disc(s) that came with
your computer originally, reinstall the OS. If you don't have them, go and
buy a new copy.