The way I run them is that for On-Access (Live Scanning) I only have Avast enabled. I just use the others periodically on-demand to make sure I have good coverage. Sometimes I disable Avast and enable AntiVir as the On-Access scanner. Anyone has other recommendations for instance to catch rootkits or other stuff? Thanks
Install firefox. Most viruses and trojans focus on msoft products. Have you tried to disable it by running msconfig.exe and take a look under the startup tab to see what is listed, most likely the trojan program will be here.
I run mcaffee and have never had a problem. What I like about it is it notifies you if something tries to change the registry which is what most trojans will do. For virus checking and cleaning I like spybot malwarebytes adaware smithfraud http://siri.urz.free.fr/Fix/SmitfraudFix_En.php combo fix It is usually best to run any virus cleaners or scans while booted in safe mode.