when I open my Out-Look Express Avast starts scanning the incoming email
after all mail is scaned the connection dialup stops and I hv to re-dial for connection /
avast does not connect or disconnect. It's an antivirus, not a connection maker (dialer) or killer.
So, most probably, your OE settings should be changed.
Can you check Tools > Options > Connection > the second option for dial-up is the one I'm talking about (Disconnecting after receiving and sending messages).