That's true, I think the slowest PC I've run it on is 1.7Ghz which was just about acceptable although it depends on what games you want to play.
As far as getting DOS compatibility working under XP you're going to have real trouble I don't really have any suggestions which might work.
You might try using some virtualisation software to install a DOS copy in a self-contained "sandbox" that way it won't affect the running of your main computer. Virtualisation has much lower overheads than emulation as it will run the CPU code natively on your hardware but will provide software peripherals. I've had some experience using Virtualbox which works well (under Linux at least) it emulates an Intel ICH AC'97 sound processor which might be compatible with older sound card drivers like SB Pro.
David NelsonTeam Leader
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Zen Internet