Hi M. Malone,
Yes, there is a way to play Generals on Lion, without having to use a DVD.
Hope this helped.
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Seriously though, try go to gameburnworld.com, and see if you can find a NO-CD patch for it. I'm assuming that Generals would be Cider-wrapped or something (if you're playing it on OS X), so if you go into the 'Show Package Contents', there should hopefully be the original .exe file to locate, and replace accordingly.
With any luck, that'll be patchable. Out of interest, how did you get it running without the DVD before? Did you apply a crack of any kind, or did it just always 'work without'?