Unable to verify your serial number.

If you encounter an error when trying to remove the .NET components with the Add/Remove programs utility, take the following steps instead (more informationOn some machines, the problem with the .NET installation will prevent the user from removing the .NET Framework through the normal means of using the Add/Remove Programs utility. In these situations, a utility has been created by Aaron Stebner (a program manager on the XNA team at Microsoft that has been working at the Microsoft since August 1999) that will automatically remove the .NET Framework installations from the computer).):

1. Click the following link to download the .NET Clean-up Utility:
   http://downloads.paloalto.com/ftp/root/cleanup_tool.exe
2. When prompted, choose to Save this file to the Desktop of the computer.
3. Once the download has completed, close any open programs and run the cleanup_tool.exe
4. Accept the license agreement and then choose to clean up .NET Framework - All Versions
5. Click the Cleanup Now button
6. Once the Cleanup is complete, close the utility and then install the latest .NET Framework (see below)