Found this out after installing IE7 Beta 2.
From McAfee tech. support:
Microsoft has released the Beta 2 Preview of the Internet Explorer 7 browser. Unfortunately, at this time our products will not work with IE7 Beta 2 Preview. Microsoft will not be patching IE7 until the Public Beta is announced. McAfee plans to support the release candidate when it is available. Please contact Microsoft for more information regarding Internet Explorer release dates.
I had no access to virus scan and privacy service, windows would open but nothing would display.
If you use McAfee and have installed IE7 Beta 2 uninstall it as follows:
Click Programs. (Windows XP Users, skip this step.)
Click Control Panel
Double-click Add/Remove Programs
Make sure the Show Updates box is checked at the top of the window
Scroll Down the list until you see "Internet Explorer 7 Beta 2 Preview"
Click the Remove Button
Follow the on screen instructions to finish the uninstall.