Virus Questions and Answers - Virus Software Conflict
Al writes in with a virus question
Question: I have a home pc with Shaw Secure, and I downloaded free avg. now the computer constantly shuts down and reboots. As soon as it boots up it shuts down.
Answer: I have seen it before where having more than one virus/security program on your computer will cause problems. For example some versions of Norton Antivirus and McAfee do not work well together on the same computer and will cause it to lock up constantly. If you can get into Safe Mode I would try to uninstall AVG and see what happens. If your computer never fully started you can select the Last Known Good Configuration from the Safe Mode menu to see if it will start up with your last settings that worked properly.
You can also try to run a System Restore to get your computer back to a prior working restore point.