System hangs following dial-up connection

[Upstream]

Hi,

Can somebody help with this issue?

Frequently, when I have successfully dialled up to my ISP, my system hangs. To clear this, I disconnect, wait around 3 minutes before the system recognises the disconnect status and then after a further 2 - 3 minutes, the system returns to normal state. During this period the processor appears idle and there is no network traffic (other than polling activity).

I am running Windows XP Pro on a high spec'd desktop PC. I run Norton Anivirus 2005 with Automatic Update but have tried turning this off, and have turned off the XP Firewall and Windows Automatic Update - this made no difference.

I also have a peer to peer network with another PC which uses a shared internet connection. The problem occurs regardless of whether this second PC is turned on.

All help will be gratefully received as this is becoming tiresome!

 

[Upstream]

A update: When the system hangs following establishing a dial-up connection, the state is not total; one application remains operational - usually MSN Messenger but can be Internet Explorer. Other applications do not respond but can be terminated and no new applications can be initiated. If I leave the system connected for long enough (> 5 minutes), it returns to normal operational state.

I can't seem to resolve this.