Cannot print to XPS unless run as administrator or UAC off

Hi,

I don't remember since when I cannot print to the XPS Document Writer driver, unless I run the program with Administrator priviledge, or if I turned off UAC. Turning off UAC is out of the question. I even tried printing a test page from the Control Panel | Printers | XPS Document Writer properties page. I can't print a test page unless I view the properties as an Administrator or with UAC off.

I looked around for solutions to reinstall the XPS Document Writer, which I tried but it didn't fix the problem.

I called Microsoft but they weren't able to help either. One tech support person gave a weird theory saying that the only reason is because my BIOS is not updated. It can't be because it used to work, until I don't know which update broke it. Out of despair I tried it too, and updated all my drivers. But as I expected, it didn't solve anything.

Has anyone experienced this problem?
How do you solve it? (Other than reinstalling Vista or going back to XP...)