I need to install the modem drivers on a Dell Dimension 2400. The computer was reformatted and Win XP reinstalled. Dell's website has a list of drivers, but I don't know which one(s) I need. It's been 10 years since I last installed modem drivers. Here's a link to the drivers on Dell's website - Modem Drivers
Go to MyComputer->RightClick->Click Properties->Click the Hardware Tab->Device Manager. See if your modem is listed and if it is shown as functioning properly. Windows XP may have installed generic Windows drivers for the modem. Do you feel comfortable enough to open the PC case and pull the modem from the PCI slot and read the Make & Model?
Use the service tag feature on the website. Will find exactly the one you need (in case Windows does not have one bundled.)