Bah another post that should go in the help forum.
Depends on your version of windows, if you have 9x (95,98,ME) just use ScummVM (
http://scummvm.sourceforge.net/) if you want a frontend for it use ScummVM Quick and Easy (
http://www.gorman.btinternet.co.uk/ScummVMQuickAndEasy1.1.zip)
Yes I could go through the whole rigmarole (uk slang, ignore where necessary) of setting up sound on 9x and probably cdrom drivers too but im lazy and besides, this isnt the help forum is it ? :D
If you are using NT (2000 or XP) then just use LEC Quick And Easy (
http://www.lucasforums.com/showthread.php?s=&threadid=79875)
It has a built in ScummVM frontend so its guaranteed* to work in one of its 2 modes...
* Guarantee not applicable in the following countries: all of them.