Hello WConway,
Do you know how Great Arcade Hits got installed on your computer?
To ask for assistance in the Malware Removal Forum there is a FAQ.
It includes instructions in post #2 on how to provide the logs from Farbar Recovery Scan Tool and aswMBR, which are the logs used in the preliminary analysis.
http://forums.spybot.info/showthread.php?t=288
But first please list:
- The operating system
- Other security programs installed
- Any other issues with the computer's performance
Best regards.