I'm afraid I have bad news...The Operating System on your machine is damaged beyond anything I can advise too try rectifying such within a forum environment. You could consider taking your machine to a reputable IT Repair Centre but being honest I am not sure if anything could be done then either(apart from my below advice)...
So my best advice would be to backup anything you wish to save and carry out a reformat and reinstallation of the Windows Operating System.
However you could try what is known as a repair of the Windows Operating System rather than a actual reformat and reinstallation. A slim chance this may work but also the distinct possibility it could worsen the overall situation. If you wish to try this I would backup first as a precaution and a tutorial on how to carry out such can be read here.
