To get MM8 working on XP, try the following (written by Manalishi66 in this thread: http://www.ntcompatible.com/thread25973-1.html)
>>I found a workaround for Might & Magic 8 that worked on my XP system. Try the following....
Start - Run (run a program)
regedit (loads the registry editor)
Search - "New World Computing" (search for the NWC string)
Make sure the Key found is "My Computer\HKEY_LOCAL_MACHINE\Software\New World Computing\Day of the Destroyer\1.0"
Change the key "3DSoundAvailable" to be '0'
Change the key "Disable3DSound" to be '1'
Exit regedit
RIGHT click on the icon for MM8 on your desktop
Select Properities
Under program name, change "mm8setup.exe" to be "mm8.exe"
Apply, and quit
You're Done, you should now be able to load and play the game, but without 3D sound (you will have standard sound)! <<
Works well on my PC.
If you cannot install MM8, try to copy all files at the CD to a folder on your Harddisk and install it from this folder.
Greetings
Rainer