..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:
Still, here's the link to the Microsoft Answers forum page:
Hope this helps.
an i can not get it off my computer an it stop working an can not down load it back on the old one