Darn! I just managed to lose the reply it took me some time to construct for you, Benjiken. Guess I need to start over. Solving .NET Framework issues can be a real hassle.
First, clean Temp Files. In order to be thorough, I suggest using the following tool:
to your desktop
- Open the file and close any other windows.
- It will close all programs itself when run, make sure to let it run uninterrupted.
- Click the Start button to begin the process. The program should not take long to finish its job
- Once its finished it should reboot your machine, if not, do this yourself to ensure a complete clean
Next, download the standalone installer for .NET Framework 4.0 from Download Details - Microsoft Download Center - Microsoft .NET Framework 4 (Standalone Installer)
Right-click the downloaded installer and "Run as Administrator".
If the above does not work, it is time to follow the suggestions provided by MSFT Aaron Stebner. Note that many of the linked articles have old dates. Aaron has updated them regularly though, including information for .NET Framework 4.
I suggest starting with the .NET Framework Setup Verification Tool User's Guide - Aaron Stebner's WebLog - Site Home - MSDN Blogs
, using the command line switch: netfx_setupverifier.exe /q:a /c:"setupverifier.exe /a"
From there, if the Troubleshooting Guide doesn't help, see Updated: what to do if other .NET Framework setup troubleshooting steps do not help - Aaron Stebner's WebLog - Site Home - MSDN Blogs
If you need to reinstall .NET Framework, see Mailbag: Should I re-install the versions of the .NET Framework in a specific order? - Aaron Stebner's WebLog - Site Home - MSDN Blogs
Please let us know how you make out.