Before you alter the IP information on your machine, use the command "ipconfig /all > filename.txt." Example: ipconfig /all > c:ipinfo.txt.
This records all of your IP information to a text file on you C: drive called ipinfo.
If you want to record the data for multiple machines and append it to a file on your network, you can use the command "ipconfig /all >> share namefilename." Example: ipconfig /all >> computer1filesnetworkIP.txt."
Using these commands will give you a reference to return to if you mess up while altering you IP information.