As far as I know, getting booted from chat programs would mean that (as already found) someone's had something on your machine that allowed them remote access to your machine. This is a Very Bad Thing. I would recommend doing the following:
I'm new to this forum and I'm having problems with people booting me from my chat programs. I have downloaded Yahoo and MSN messenger but my main problem is with Yahoo. When I go into the Yahoo chat rooms and someone comes in there to boot people, I get the big KAPOW!!! What I'm looking for is a program, that I can download, that will keep this from happening to me. I read some of the things that JP has written on here and followed his advice on one thing and that was "The Cleaner". I downloaded that program yesterday and it detected a trojan in my system and cleaned it out (Thanks JP) but I am still looking for a good boot protection program. I would sure appreciate any feedback.