Unity 4.3.4f Compilation failed because the compiler couldn't be executed!

I have looked around and cant find a solution to this problem and have never had it before. I have just recently updated unity from 4.0.0 to the new one but am have this error and have googled the problem and have come to a blank. I have tried reinstalling it and rebooting my laptop none seem to fix the problem. If anyone could help I would be obliged.

Errors in console window:

sorry i haven’t posted on how to fix this it was a while ago and i have kinda forgotten about this account. I deleted unity in the windows explorer but kept monodevelop then installed unity without monodevelop and went into the settings and changed the compiler to the old monodevelop and voila it worked.