The two programms aren't both antivirus programms- Immunet Protect is a additional type of program more like an antispyware, from all the articles I've read. it should not interfere with avast.
AnVir and Panda USB Vaccine have been running on this pc for nearly a year, so I'm sure enough none of those programs is causing this.
I know that gmer is a scanner, but I cannot think of anything else that might have caused this performance loss- I didn't install or run anything else new this week.
I'll have to be away for a few days, so I'll scan and post the eset log on monday, I hope it's not a problem.