Malware - viruses, trojans, worms etc can install in many different places and often reappear after cleaning, you need to make sure you have removed it completely by a full scan in safe mode:
Reboot and press f8 key repeatedly until you get to safe mode, run McAffee
you could also try a safe mode scan with the following free antimalware products - download and update before you reboot into safe mode!
--Free Anti Spyware--
Malwarebytes click here
Spybot S&D click here
A squared click here