Windows2000 PC does not respond to PINGs

I have a Windows 2000 PC (call it A) that is not responding to ICMP packets although it can issue PINGs to other machines (e.g. B) and receive positive replies. NetBEUI works fine in both directions (A to B and B to A)

A can see B’s MAC address in its ARP cache and B can see A’s MAC address.

When B pings A, if the LAN Status window is open on A, you can see the number of Received packets increases with each ICMP packet sent from B but the number of sent packets on A remains static.

I have removed and reinstalled TCP/IP on A as well as the adapter. All other machines on the LAN work fine. The problem is definitely with A. I have tried different network cables and hub ports.

Any ideas gratefully received,

Danny