There is an adbrite virus.
Open your task manager, click on the processes tab and look for AdBrite.exe.
If you see it listed, you have the adbrite virus. Most virus scanners don't pick it up. You might be able to get rid of it using Malware Bytes or Spybot S&D.
I would suggest running Malware Bytes on you machine anyway as part of your regular maintenance cycle.