First, it depends on if we're talking about the DOS (floppy or Collector's CD-ROM) or Windows (bundled w/ TIE Fighter et. al in either the X-Wing Collectors Series [with X-Wing vs. TIE Fighter: Flight School] or the X-Wing Trilogy [with X-Wing Alliance]). I'm guessing with the machine you'd been running it on, you have a DOS version running either in pure DOS or something like Windows 95. If it is the DOS version, you'll probably have to install and run the game under DOS emulation. This can be done with DOSBox (http://www.dosbox.com
), but you may need VDMSound (http://vdmsound.sourceforge.net
) as well, to emulate support for "legacy" hardware (X-Wing may not be able to recognize a newer soundcard in the DOS virtual machine, but VDMSound would allow X-Wing to "see" it as a SoundBlaster-compatible card.).
Hope this helps. A thread on TheForce.net's forums
goes into running all types of old DOS games (including X-Wing and TIE Fighter) under DOS emulation, so you may want to check that out, as well.
Failing that, you may want to check into getting a copy of one of the Windows bundles I mentioned above, but you'll also need the 3D compatibility fix on LucasFiles.com, and you may need the latest version of "XWA Hacker," as well (Google search that, narrowing the site to www.xwaupgrade.com