I went to User Accounts in Control Panel (Vista) and turned off the User Account Control thus "elevating" me to a higher Administrator status. I erased my unused disc space then turned the account control on after I finished. It worked for me. Gerry
To save your time, you can try right-clicking the shortcut and click Run as Administrator. I tried this with Vista myself and it works, though I did get a report that it doesn't work. Can you check if it does?