Left click on the .exe file and go to properties. Go to the compatibility tab and you'll see where it says set compatibiliy mode. set it to windows 95 and it should work.
Uhh.. No, everyone says that but that NEVER works...
[ The version of this file is not compatible with the version of Windows you're running. Check your computer's system information to see whether you need an x86 (32-bit) or x64 (64-bit) version of the program, and then contact the software publisher. ]
Changing the compatibility to windows 95 DOES NOT WORK IN VISTA, and it STILL DOESNT WORK with any other program, people need to stop saying "put compatability to windows 95" It does.... Not... Work...
Is it Vista 64-bit? 64-bit versions of Windows cannot run 16-bit applications, which is what COTW is.
What you might try:
running a 32-bit version of Windows, possibly in a virtual machine such as VMWare or VirtualBox (there's a version of VirtualBox that is free) and run COTW in that.
if you don't have a 32-bit version of Windows and don't want to buy one, try running Linux in VirtualBox and use Wine to run COTW (COTW runs 99% under Wine). (this option uses all free software)
run a really old Windows (e.g. Windows 3.1) in DOSBox and run COTW in that. This is probably simpler than the other two options.
i'm trying to run cotw on the DOSbox i kept trying to find a way for it to work and right when i think i have everything right (creating a shortcut that uses both the dosbox.exe and the castle1.exe)