1. Open Visual Studio Command Prompt (2010) under Start menu -> All Programs -> Microsoft Visual Studio 2010 -> Visual Studio Tools (run it with Administrator privilege: right-click the program -> Run as administrator);
2. Try some devenv switches in command prompt:
a. Rundevenv /Resetsettings to eliminate the cause of corrupted settings.
b. Rundevenv /ResetSkipPkgs in Command Prompt.
c. Rundevenv /Safemode to see if you can apply it correctly. This can eliminate the possibility that third party Add-ins or packages are causing problems.
3. Reboot the machine inSafe Mode. This can isolate some third party application/driver's interference.
4. Switch and try a new user account. This can rule out the possibility of corrupted user profile.
source:msdn