10.2 Home Use won't authorize

I just purchased ArcGIS 10.2 for home use, installed over 10.1 Basic, and installation appeared to proceed ok. All the programs are there in the Start Menu. When I try to start ArcGIS Administrator (think that's what it's called, at work now) to authorize Arc, a message box pops up asking if I allow it to make changes to the system. Click OK, the pop up disappears and nothing happens. Now I can't use Arc because I can't authorize it. Any ideas? Thanks.

Windows 7 Pro, Net 4.0