[quote="hcmcdole"]Good call Doug. I guess I thought no one uses a dial up modem any longer but...[/quote]
I've seen all kinds of numbers but I suspect it is at least 10%, most likely more, maybe much more. Some rural counties may be as high as 70 or 80 percent. I know it wasn't available to me until about 2 years ago and then the few lines that could get it were quickly sucked up and it was another 6 months for more to come available.
If it is a separate board simply open the case, remove the one screw holding the modem in, remove the old modem and and then follow the above directions in reverse for the new modem. Of course the computer needs to be turned off. When I'm working on a computer I usually turn it off at the power strip or at the switch on the back. I do leave it plugged in so that it is grounded and I make sure I tough the frame of the computer before I touch anything inside to make sure there is no static built up between the computer and me.
If it is built into the motherboard you most likely will have to go into the BIOS settings and disable the modem on the board. Then you can install the new one.
When you turn the computer on windows should try to install software for the modem. If it is successful then you are done. If it isn't and the new modem came with a disk, follow the direction on the disk.
I encourage you to think about an external modem. After I went from a winmoden in a laptop to an external modem on a desktop I had many fewer dropped connections and about 20% faster connection. I don't know how much they are now but I paid around 50 from Newegg for mine.
I also recommend a surge protector that you plug you phone line into also. Phone lines are common ways for lighting damage to occur.
It doesn't have to be an external modem. They make internal "hardware" modems (different from winmodems). A winmodem uses the computers RAM and CPU cycles to "do it's thing". It uses Windows for it's software, and will be plug & play, which makes for an easy install but a waste of the computer's resources. A hardware modem will contain it's own hardware needed to connect. It's much more stable than a winmodem, and cheaper than an external. It's drawback is it needs drivers installed, specific to it's hardware (a disk will come with it).
Also, if the current modem is built into the mainboard, it shouldn't be necessary to disable in BIOS. The new card will simply be shown in Networking properties, and the connection enabled (as well as the onboard modem, disabled) from there. I only bring this up, because a user asking about the simplicity of swapping out a card probably doesn't know what the BIOS is, or how to enter it. I wouldn't point them in the direction of the BIOS or the Registry, unless it's absolutely necessary (it usually isn't). Many bad things can happen in either area, by clicking on the wrong thing. =)