Vista Home lacks the GUI to manage local groups which means the group membership of any user you create will be fixed at creation time. Not such a bad deal for most home environments but if you're running Samurize, like me, it's a problem if you want to gather and display performance statistics. It's a problem that's been discussed over in their forums for a while. While the GUI is absent, you can do it from the command-line.
NET LOCALGROUP "Performance Monitor Users" username /ADD
will do it. You need to run the command in administrative mode and the easiest way I've found to do that is to type "cmd" in the search box but, intead of hitting ENTER, hit SHIFT-ENTER. Respond Continue to the UAC prompt and the Dos-like box is running as a full Administrative user. And while you're at it, check out all of the NET commands -- NET /?.
(I'm going to post this over in the Samurize forums but I want to give you all a first-shot at it.)