So I recently set up a Windows XP machine for older titles that originally released on XP and since I legally own some games through GOG like the Dawn of War titles, I'd rather get them from legitimate sources rather than pirating them elsewhere.

I can install the games fine, but when I go to run them it complains that they are not Win32 applications. But these definitely worked back in the day, so they should be Win32 applications. Does anyone know what GOG did to the game to prevent them from running as such? and if so, is it also possible to reverse that in some way?

So, I have not tried to get these games running on WinXP, so I'm not sure if what I'm going to write will help or not.

I am a Linux gamer, but many games for Windows run via Wine on Linux.

One item I've noticed with GOG games is that it is easier to get them to run by going into the actual folder and running it from the exe file in the folder. I think the Icons are more of a connector to the actual game files.

You could try seeing in the folder themselves and running it via the exe and see if that works. Occasionally there will be multiple exe files in there as well, so if one doesn't run it, another may.

Going out on a limb I would guess you are running it from the desktop which is likely calling for the GOG launcher to then launch DoW, rather than just launch DoW.

The GoG DoW is unfortunately the worst version, steam is the best but alas will not work on your XP rig I suppose. Only an issue if you want to play with big mods anyway.