Network connection drop at specific time

I have a Windows 2000 client that just within the past week started having a strange problem. This client has been on Windows 2000 for over 8 months. None of the client’s hardware or software has been changed since installing W2K. Staring last week, the network connection for this client will dropp automatically at 4:00PM and will re-establish at 4:02PM. Every day at the same time. Network is Windows-based network. I do not have any other clients on this small LAN (around 40 clients) that have this problem. I know that the connection is not dropping at any other time, because I have a small batch file that is looping across the ‘time’ and ‘ping’ commands against this client 24/7, just to prove to myself that it was always happening atthe exact same time every day. It is.