okay, it started with the "updatesearches.com" problem, which i fixed following instructions in this forum (thanks guys!).
antivir xp was also finding four trojans which it couldn't delete, or rather kept deleting and then finding again:
anyway, after following all the instuctions, when running cleanup! i got a message that some parts of windows were incomplete or damaged or something, when it asked me to insert ´the windows xp cd nothing happened.
my computer is still running very slowly. i ran antivir again, and it found and deleted the trojans again, and hasn't found them again so far, which of course isn't to say they're gone.
anyway, now for the dumb part: i tried to follow the instructions in the forum on how patch holes in windows by booting from the disk, but either i'm too dumb and messed it up, or it never gave me the option to update the current windows. anyway, now i have another windows xp installed right alongside my normal windows, can't uninstall it, and still don't know if i still have trojans or not. also, hijackthis! is still finding that msmsgs.exe, and other processes that i don't recognise, and quicktime is in the autostartmenu since this whole thing started.