There other types of programs that hide in the computer and hard to locate. I had that experience and all the time it keep say comet I finally had to do a Qucik Restore where I strip the whole hard drive like new and started over the troube left!
Now all I have on my tool bar is MyYahoo, Hotbar, Comet Dictionary (no cursor) Comet aka Starware!
I have no trouble with trojan or backdoor parasites!
I also put AntVirus to protect me from these intruders!
Well since I found 59 other buggers besides the Comet thingy .. that may have contribute to the slowness of my computer
I have been having the slowness problem for a while .. it was so bad it reminded me of when I was back on dial up
I thought I had everything covered .. I have zone alarm .. Norton and various other stuff to do scans and clean things up .. but somehow it didn't stop them all
But then .. the girls are know to shut down the zone alarm when going into a couple of sites .. so that's probably how it got on my computer