64bit internet browser works, but 32bit aren't.

Hi All.

I'm not sure what caused this weird symptom. but I still doubt Avast!
anti-virus.
after installed Avast free-home AV apps onto my vista 64 ultimate.
almost every network releated apps aren't running. (mostly 32 bit apps.)
include latest firefox, google chrome browser, 32bit internet explorer
brothas.

but 64 bit internet explorer is surely works. (maybe it's only network-app
that I can use.)

problem is, avast uninstalltion isn't work either!
so I removed manually, services, registries but no luck.

fyi.
pinging, ftp via Command works
mostly, games, media players streaming, apps are NOT works.

and there is no suspicious log in Event Viewer.
Network Center says "no problem".

anyone out there shed a bright light onto me?

Thanks in advance.