Uninstall IE8 beta 2 without IE8 folder (go back to IE8 beta 1)

I have found that some software I have does not work with IE8B2
(worked with IE8B1). Some sofware chrashes in "mshtml.dll", and
some websites (.net archive system) crashes when drop down menues is
about to be shown on buttons (error about unknown function in script)

I need to get rid of the IE8 beta 2 and go back to beta 1 or IE7 !

But I have installed XP SP3 after installing beta 1, and the uninstall
files are removed (don't ask how, they are just not there).

But the beta 2 has been installed after SP3 so that could be removed.

BUT, the uninstall files for that one is gone as well (no "ie8") !!!!

So what then? Is there a manual way to go back to IE8 beta 1 or IE7.

If i try installing the beta 1 it won't because a newer version is
allready installed - but is there a way to trick it to overwrite that?
--
Lars-Erik Østerud : http://www.osterud.name

Firefox tweaks: http://firefox.osterud.name