won’t accept changes to TCP/IP settings

I have a Win2K Pro SP2 system — actually several systems installed from the same image on identical hardware — that refuses to accept any changes to the settings of the TCP/IP properties. If I try to assign a static IP address, gateway, DNS and WINS server addresses, I can enter them in fine, but as soon as I click Okay, then re-open the properties, everything I entered is gone and all the settings are back to the default values for dynamic addressing. I’m logged in as the Administrator, and I’ve tried different ethernet cards, and the problem persists. Anybody seen this and devised a solution? FYI networking works just fine, but only because my company is beta testing the DHCP dynammic addressing. I want my static address!