To me it sounds like windows is corrupt. It was probably a driver update or just an update from MS themselves. If you can not do a system restore because it will not let you it also could be a virus. If it works in safe mode go there back up your files and wipe it and re-install the OS. Make sure you scan your files with a antivirus before you dump them back. In the long run you will probably end up saving time going this route. The bonus is Windows will be quicker with a fresh install.