The only thing I would add to Sgt_Shultz posting is that if you are going to disable the built-in modem, you should first go to Control Panel / Modems and remove that modem from there.
As long as you have Dial-Up-Networking version 1.4 installed,you should not have any problems with both modems installed.
You will need to find a "dongle" cable for that specific modem before you can use it.
If you look at the outside edge of the card, you should see a small connector. This is where youplug the dongle cable.
One more note on PCMCIA cards, you need to use the card icon in the system tray and disable the card before removing the card while Windows is running.
As to awarding Tech Points for multiple answers, this is from the Technical Q&A FAQ:
Please also note that if you select more than one acceptable answer, the total number of TechPoints you assigned to the question will be evenly distributed.
So, with 250 points, if you rate 8 answers as acceptable, each peer would get 31 points.
Chas