VisualStudio debug attach to process does not show w3p IIS web publishing in the list of processes

I was debugging an ASP.Net application using VisualStudio and attaching the debugger to the w3p process.
Sometimes, the list of processes to attach to, does not show the w3p process.

How-I-fixed-it:
Here are some steps, that made the w3p process appear again in the list:
- Rebuild the solution
- Restart VisualStudio
- Logout from Windows and log in again
- Open the web application to be debugged in a browser window (this finally solved the problem on my computer)

This list of steps is a "best-of" the solution, i collected from the following sources:
http://stackoverflow.com/questions/1983439/why-cant-i-attach-to-the-w3wp-exe-process-when-i-turn-off-just-my-code-in-vs201
http://stackoverflow.com/questions/4313206/cannot-attach-debugger-to-w3wp

Visual Studio 2010 wont start after uninstall .NET-Framework 4.5 / Unknwon error

I did some tests with .NET-Framework 4.5 on my computer. After uninstalling it, i recognized, my Visual Studio 2010 does not start any more. It shown an "Unkonwn error" message box at startup an then closes again.

How-I-fixed-it:
I found out, that uninstalling .NET 4.5 also uninstall .NET Framework 4. I re-installed .NET 4 from http://www.microsoft.com/de-de/download/details.aspx?id=17718 and Visual Studio was working fine.

I found the right hints here:
http://chanmingman.wordpress.com/2012/05/10/unknown-error-to-prevent-vs-2010-from-start-after-uninstall-vs-11-beta/