MediaPortal 1.20 on Guest Account, Windows 7 (1 Viewer)

[Nordfinn]

I want to enable a guest to watch OTA tv on the guest account on my desktop PC, running Windows 7 (Home, 32-bit). I give guest full control in Permissions, and yet I can't open MP on the guest account without running as Administrator. I realize this may be a Windows question, ultimately, but can anyone give me a hint? I had this working this way previously, with a previous version of MP, so I think it should be possible.

Thanks.