Do you have teamviewer or any sort of remoting software installed?
Either that or you're going into the matrix soon.
EDIT: Start that puppy in safe mode, see what happens.
Check MSConfig to see what's running at startup
Check HiJackThis and check the log
Run a scan with Malwarebytes and whatever your AV is if you see anything amiss.
If all else fails, especially if you have sensitive data on the drive, yank it, get it on a secure computer with good AV, transfer data and reformat.