Well, firstly, if you haven't already, download Tomb Raider <html><a href=
http://www.dosgames.com/g_3d.php>here</a></html>.
Now then, wait for the download to complete then click "Open" on the friendly little window that pops up and use Winzip to unzip it to any category you want... say, "C:\Traider." If you don't have Winzip, you can download it <html><a href=
http://www.winzip.com/>here</a></html>. I strongly recomend buying the full version, it makes it a LOT less annoying and easier to use.
Now, click "Start", "Shutdown", "restart in MS DOS Mode" and click okay.
Now, once you're in DOS, type CD\
Type CLS (not necisary, just cleans up the screen)
Type CD\Traider
Type Setup.exe
Configure Tomb Raiders settings to your personal flavour.
Save and Exit.
Type Tomb.exe.
And you should be running!