See if clean boot helps solve the problem
Csc.exe file description
Productname: Microsoft® Visual Studio® 2005
Description: Visual C# Command Line Compiler
Company: Microsoft Corporation
A Microsoft Driver
Try an sfc scan first, it may be repaired.
http://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html
Then if necessary
How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7
It checks, you can get a written report if you want. I will tell you how if interested.
It can fix basic OS corruption. If it show errors run 3 or 4 times, it does not fix all at once.
Here you Go
Open another elevated Command Prompt and paste this command into it:
findstr /c:"[SR]" %windir%\logs\cbs\cbs.log
This will show all the files you want to see in the Command Prompt window.
Since that window is not very practical for a detailed study, you want to paste the content into a Notepad, Wordpad or Word file.
For that you right click on the Command Prompt window (any place is good) and click Select All. Then you right click anywhere in the window. Now this whole text is stored on the clipboard and you can paste it into a document file (e.g. Notepad) where you can analyze it.
Special thanks to WHS for this information
rb: Windows Update) Microsoft.NET Framework 4! This problem come in my case, sometimes when the service "Offline Files" is disabled.