I am running Windows 8 Pro x64. Never had a problem with .net applications and I have a few I use daily for my business.
I installed Visual Studio Express 2012 for Desktops. After installing this, all .net applications (including VS) crash on startup. They will show the UI then crash immediately saying it "stopped working", some crash after hitting a button in the UI, most crash just after the UI is loaded.
Uninstalling VS does not restore the functionality. I disabled AV, no difference. I used the .Net diag tool and confirmed 4.0 and 4.5 .net are installed correctly. I did a repair on VS but no change.
Now with VS uninstalled, I am still unable to run any .net applications without crashes.
Eventlog gives me an Event ID 1000, faulting module KERNELBASE.EXE. With no other usable details.