I would look for a better AV scanner, I personally use Kaspersky's KVRT.EXE which I download when I need it, run it then delete it. I absolutely don't want an AV scanner running all the time, if you have reasons to secure your computer for other people to use, set yourself up a separate profile that does not run the AV scanner all the time. On all of my boxes I have the default Microsoft AV running and it never caused me a problem.
While I was configuring one of the machines recently my catch it all "StartupMonitor" blocked something that was trying to install at startup so I used KVRT to fully remove it and it worked really well.
