I have a Windows XP system that I still use off-line for a few tasks. I am the only user of it and my account is listed in Windows as an 'Administrator'. However, when I try to load programs onto it, I get a Windows error message: "The installer has insufficient privileges to access the directory". (e.g.: C:\Program Files\Microsoft\Windows 7 Upgrade Advisor.) "The installation cannot continue. Log on as an administrator." Since I am already logged on as an administrator when using that PC, how can I fix it to give the installer all privileges?