Microsoft is offering for download the .NET Framework Cleanup Tool as well as the .NET Framework Setup Verification Tool, both of which’ve been tailored to Windows 7.

-.NET Framework Cleanup Tool allows you to remove .NET Framework 2.0 SP2, 3.0 SP2 and 3.5 SP1. The .NET Framework Cleanup Tool serves to clean up all traces of the framework, including from registry, but also the actual files, in the eventuality of a failed installation.
-.NET Framework Setup Verification Tool is designed to automatically perform a set of steps to verify the installation state of one or more versions of the .NET Framework on a computer.  It will verify the presence of files, directories, registry keys and values for the .NET Framework.  It will also verify that simple applications that use the .NET Framework can be run correctly.