I thought I might chime in here.
Getting older games from my childhood to work on my current computer has been an obsession of mine. Here are a couple of helpful links for slowdown programs and general info:
http://www.oldskool.org/
http://www.oldskool.org/guides/oldonnew/resources
Also check the forums at:
http://www.the-underdogs.org/forum/viewforum.php?f=4&sid=81b083fce21140c68ee64bcc25c6e32d
What I finally found to work best is a generic boot disk program called Behive OS. This program will crate a boot disk that will boot you into DOS and give you several options to configure your memory. It also has generic CD-ROM and mouse drivers. I have managed to get both X-com and MOO running with it. You can get it here:
http://community.the-underdogs.org/pub/bootdisks/
The file is called whive12.exe Just pop a floppy into your drive and run it. It will even get you into a “true” DOS mode running windows XP!
This boot disk doesn’t do anything for speed issues but if you combine it with some of the slowdown programs found at oldskool.org you can get most games working well. This should work for most people.
I have a lot of experience dinking around with stuff like this, so if anyone has a question or problem I may be able to help. I also proficient in DOS if anyone needs some help getting past A:\