NT / 2000 – ISA Server – Proxy client

I am in a NT4.0 domain, mixed with 2000 servers. I have been asked to config the ISA server for a web proxy (running fine). The next part is the deployment of the proxy to the clients pc’s. We want to install the proxy and lock down the ability of users to bypass the proxy by going to Internet Tools. I am wanting to do this without the touching of the desktops unless absolutly needed. I am looking for a script or reg config that I can change remotely.

I know that if we had AD deployed, this would be a walk in the park – quick. We have ISA installed on 2000AS.

Any thoughts or ideas….
TIA
Fly