Did the Linksys card come from Dell or is it a retail add-on card?
If it came from Dell, preinstalled in the computer, then you should be able to find a suitable driver from Dell providing they shipped this computer with Windows XP installed.
If the card is a retail card from Linksys, then you should be able to find a suitable driver from the Linksys website.
It's difficult to help when you leave out all the important details. Atop those lacking details, I believe you gave the wrong Linksys model number. Linksys never made a line100tx card, they did however, make a lne100tx
card. They also made it in several different versions each requiring a unique driver. ie: Version 1.0, Version 4.0, and Version 5.1.
Linksys drivers are here: [url]http://homesupport.cisco.com/en-us/wireless/lbc/LNE100TX[/url]