..your best option is to report such problems to the IE9 beta response team.. As you know, beta projects are "not ready for prime time" programs and as such, are best left to experts who know how to deal with such problems.. You are such an expert, correct?

Here is one such discussion about a possible way to remove IE9 beta:

http://social.answers.microsoft.com/Forums/en-US/InternetExplorer/thread/7250c2d2-20e1-4f0a-8056-4a6abd9a0f9b

Still, here's the link to the Microsoft Answers forum page:

http://social.answers.microsoft.com/Forums/en-US/answersfeedback/threads/

Hope this helps.

Grif