I just spent a few days with a customer who had issues uninstalling Beta 2 and then installing the RC candidate.
Here's a snippet from his MSI log:
MSI (s) (44:28) [20:59:55:916]: Executing op: ServiceInstall(Name=msvsmon80,DisplayName=Visual Studio 2005 Remote Debugger,ImagePath="C:\Program Files\Microsoft Visual Studio 8\Common7\IDE\Remote Debugger\x86\msvsmon.exe" /service msvsmon80,ServiceType=16,StartType=4,ErrorControl=0,,,,StartName=LocalSystem,Password=**********,Description=Allows members of the Administrators group to remotely debug server applications using Visual Studio 2005. Use the Visual Studio 2005 Remote Debugging Configuration Wizard to enable this service.)
Info 1923. Service 'Visual Studio 2005 Remote Debugger' (msvsmon80) could not be installed. Verify that you have sufficient privileges to install system services.
If you see this issue, the workaround is:
Find the following registry key:
Delete the registry key and then try to reinstall.