Ditto on malwarebytes. Also, create a new user which is an administrater and log in under that name, then download and run malwarebytes.
Mega-ditto!
Once you get the computer cleaned up, I highly recommend Avast Free Antivirus. It has, so far for me, proven to be much more effective than AVG Free Antivirus and it is much less intrusive than Norton or McAfee. It also offers the option to do a boot scan for viruses and malware and this has been vital in removing tough viruses and malware from several systems I have had to do work on.
Good Luck!