When I tried to uninstall all parts of Visual Studio.Net 2005 Beta 1 Refresh to install the latest version Visual Studio.Net 2005 for the SQL Server 2005 CTP I had a problem to uninstall the Microsoft.Net Framework 2.0 Beta with Add/Remove Programs:

This is caused by a wrong uninstall string in the registry.
To uninstall it manually you must use:
msiexec /uninstall "C:\WINDOWS\Microsoft.NET\Framework\v2.0.40607\Microsoft .NET Framework 2.0 Beta\netfx.msi"
Afterwards you can install the new version.
As Rob Caron states in his Blog http://blogs.msdn.com/robcaron/ you have to deselect the following components from the install:
- Testing Tools
- Performance Tools
- Static Analysis Tools
Otherwise an error while installation Visual Studio.Net 2005 will occur.