Problem :To Uninstall Windows Update like IE 7.0

since this is a Beta release....so this should appear at an Installed Hotfix....
or as an Update....here is what should help you..

To uninstall Internet Explorer 7 Beta 2 Preview and return to Internet Explorer 6
1)on Windows XP Click “Start,” and then click “Control Panel.”
Click “Add or Remove Programs.”
Check “Show Updates” at the top of the dialog box.
Scroll down the list to “Windows XP – Software Updates,”
Select “Internet Explorer 7 Beta 2Preview,” and then click "Change/Remove."

2)If "Internet Explorer 7 Beta 2 Preview" does not exist, run :
%windir%\$NtUninstallie7bet2p$\spuninst\spuninst.exe.
You need to have "view hidden folders" enabled.
%windir% is your Windows installation directory,
which is normally 'C:\Windows' on most systems.