gary,
Most dial-up ISPs assign dynamic (changes every time you logon) IP addresses because they share the modems and IP addresses with other customers when you are not connected. But with broadband (cable or DSL), you are always connected, thus your IP address stays the same most of the time.
You might be able to get a different IP address by releasing your current IP address and turning your computer off overnight. Do this by opening up the "Network Connections" window and right-click on the "local Area Connection" and select "Disable". Then shutdown the computer. When you start it back up, you may need to "Enable" the connection again. This will take several seconds to complete. No guarantees, but it might be worth a try.
The email account is totally separate from the IP address. It would just be a different email address so they would not know it was the same as your current email address, i.e another way of determining it is the same person.
Good luck. Ron