If you have two separate NICs, & are only going to be using one at a time, set them up using hardware profiles. Use one hardware profile for work, & one for home. When your computer is turned on, it will give you a choice between the two profiles. Just pick your location, make sure the proper NIC is in, & go.
The easiest way to set this up would be to uninstall BOTH NICs, & clear out your network stack save for maybe the dial up adapter if you use it.
Then, right click your My Computer icon, & choose properties. Go to the Hardware Profiles tab. Select Original Configuration, & choose copy. Type in a name for one of your profiles, say "LAN at work." Hit OK, & then make another copy of Original Configuration for your home connection, name it "DSL at home." Hit OK. Reboot your computer. Windows should offer you three hardware profiles to choose from. Don't mess with Original, leave it in case you FUBAR something. Choose one of the other two, & install your NIC & configure as necessary. Repeat for the other one. You could even use the SAME NIC, & just configure the hardware profiles differently.
FYI...
I don't care how much "experience" you've had, you're full of sh!t. It's very much possible. It's even possible to have two NICs installed on ONE hardware profile (How the fvck do you think a NT based firewall works?), but given his situation I'd say hardware profiles are the easiest solution.
Viper GTS