Visual Studio 2013 Not Running

I am faced with the same issue. I was having a working VS2013 installation once I created a new login it stopped working.

For now I am adjusting with run devenv from command prompt

devenv /resetsettings

Then run the reset settings from the IDE. Tools menu-> Export Settings->the Import and Export Settings Wizard page-> Reset all settings

Uninstalling "HTTP Debugger" solved my problem.

It seems it had conflicts with VS2012, 2013 & Firefox and somehow was blocking some network access. After uninstalling HTTP Debugger All of them work properly.