Solution by Der8auer:

 

Found the solution for this problem

 

When .NET redistributable is installed, it compiles the high priority assemblies in 5 to 10 minutes and then waits until your computer is idle to process the low priority assemblies. The following method forces all of the remaining items to be compiled with a command called NGEN.exe. Follow these steps:

 

1) Run cmd.exe from Start > Run

 

2) Type cd\

 

3) Type cd Windows\Microsoft.NET\Framework\v2.0.50727

 

4) Type NGEN executequeueditems and press Enter

 

5) It will take about 1-10minutes depending upon system speed. After the process is complete, the following prompt will appear in the command prompt

 

C:\Windows\Microsoft.NET\Framework\v2.0.50727>

 

6) Type exit to close the command prompt.

After performing these steps, your computer will boot up at usual speed.

 

http://hwbot.org/forum/showpost.php?p=146099&postcount=75

This works too

 

cd Windows\Microsoft.NET\Framework\v4.xxx

NGEN update