[Endoperez]

The '-w switch' is a command line switch. In dos, it would be used like this:

C:\Games\Illwinter\Dominions II\>dom2 -w

In Windowses, you can use dos promp. Click Start, click Run, write 'cmd', and a black window with white text that looks and acts very much like DOS pops up. Most dos commands work for it, and you can go to your Dominions II directory and test if the game works with this.

If it works, you want it to be easily usable. This can be done with the help of shortcut, like the one that probably is on your desktop. Right-click on the DomII icon (Belphegor the Lord of Corruption, IIRC) and choose properties. Now you should be able to write in the target (for me "E:\Dominions II\dom2.exe") amd working folder (for me "E:\Dominions II"). You just have to add the '-w' to the end of the target line. It seems it has to added outside the quotes, like this:
"E:\Dominions II\dom2.exe" -w

You might not have the words "target" and "working folder" in there, because those are direct translations from my Finnish windows's respective words.2