Data Execution Prevention is KILLING me?

Ok, so all my files except my Internet, and games will not open for anything. I get a DEP error for EVERYTHING. I cannot access my music folders, pictures folders...ANY FOLDERS! I am completely unable to access 'My Computer' or 'Control Panel' or even 'Search'; each come up with a DEP error. explain if there is something I can do without calling microsoft or crashing my computer.