How to Change the IP address and Subnet mask

Eep, nasty question, hard ;) The best bet, I think, would be to dig around in your registry or the windows folder. I assume things like your IP and subnet mask are stored in the registry. Also, if you can find a decompiled version of Windows, which is nearly impossible but I heard tell of one once, you can look at the winipcfg program and see how it does it... beyond that, maybe try sending an e-mail to Microsoft asking them where they store that kind of info? They probably won't tell you but it might be worth a try.