This game runs on Windows XP. No problems detected. You only need apply the patch and you're all set.
The CD installer doesn't work on Vista or later Windows systems! If you don't have the installed gamefiles, e.g. from an old installation, go for Markus Egger's msi version of the installer! Documentation can be found there!
Install it by hand! Copy over the installed files from an older system - if you have them - to your hard drive. Then set up the registry by hand.
Check out Markus' website. There also should be an installer for 64-bit Windows Vista or later.
You will need the 2.02 Update to play XWA online. Please download and install it.
Your firewall has to allow
XWINGALLIANCE.EXE located in your XWA game folder.
If you experience trouble with the graphics or other things in XWA, go to download and check for a fix there.