Latest Update Problem

I use Windows 2000 Pro. Right after the latest Avast update, rundll32.exe hangs and prevents Firefox and Thunderbird from loading. So I had to uninstall Avast to recover. What next?

Any rundll32.exe instance, or just one particular rundll32? (with specific command line, I mean)
What happened when you started Firefox and Thunderbird?
Does it help just to stop avast! resident protection?

The particular rundll32 is not displayed at shutdown, but I have also had trouble with printing, Windows Explorer network tree, and hmmm, can’t remember now what else.
All problems disappeared when I uninstalled Avast!. Stopping resident protection did not seem to help.
Incidentally, first time I tried to uninstall using Add/Remove Program, the Uninstall for Avast! hung too.
ZoneAlarm has Allow permission for all of the internet applications.