I have a Dell Dimension 8100 running a P4, 1.4ghz & 256mb ram.  It came with WinME, and I'm starting to wish I'd saved a few bucks & had Win98SE put on it instead.  I 've experienced alot of browser lock-ups, not just in IE, Netscape doesn't seem to fair much better.  I've been seriously thinking of repartitioning the HD and trying out 98se on another partition to see how it performs.  My most frequent error seems to be with KERNEL32, I get errors with it at least once a day that cause whatever browser I'm using to shut down.
A couple of folks have suggested I opt for going to Win2000nt, but then I've also read posts on other bds similar to this one that some people have problems with that o/s also.  I personally think you're better off going with a more stable system like 98se, since it's already got the bugs worked out of it.  As for MSFT's new brainchild, XP, well before I'd put that on any of my machines, I'd wait for them to get their security issues worked out.  To learn more about this check out this link from Steve Gibson, developer of Zonealarm & ShieldsUP.  http://grc.com/dos/intro.htm  You'll learn why hacker types love this new o/s