Contant Unity 3D 4.3 crash. What to do?

I have reinstalled this program many times and still it crashes. I have sent countless reports and have yet to recieve any help.

This happens at start up with Unity 3D. A Fatal Error message always comes up, reading:

GetPersistenManager (). WriteFileInternal
(metaDataPath, metaDataFileIndex,
writeData.begin(), writeData.size(), NULL,
BuildTargetSelection::NoTarget(),0)

I am a beginner code monkey so I have no clue what it means or what it does.

This always happens whenever I try deploying Unity 3D (this is the free version, as well)

Failure to Start