Vista - Shared Computer Toolkit

Have just upgraded from XP Home to Vista Premium Home and love it. HOwever,
in the upgrade, I left Shared computer toolkit in place and although there is
no (or certainly not enough) unallocated space after the C:\ Drive where
Vista is installed, the Disk Protection keeps telling me that it is "On".
This is in spite of the fact that I never had it turned to "on" before I
upgraded and I don't think it is working anyway because I am able to modify
C:\

I have tried uninstalling the toolkit, but when I try, it keeps telling me
that I need to be an adiministrator - which I am. Then I get a window asking
me to verify my Windows installation (which is genuine) and then the whole
thing closes down. How can I uninstall the shared computer toolkit now?

Thanks.
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Thanks - Ted