Is your copy of the Windows 7 RC a legitimate one? There have been articles in the Washington Post, eWeek and other outlets about infected, pirated copies of Windows 7

If you got your copy from a non Microsoft outlet, please download the RC from http://microsoft.com/springboard, wipe your machine and reinstall.

For more info on read this piece here: http://blogs.zdnet.com/security/?p=3370&tag=nl.e539 

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