Worked fine until a couple of weeks ago. Now I get the message that it has stopped working when I launch the game.

What gives? Get the message that the game has stopped working and WIndows is searchig for a solution.

Very disappointed.

You may want to post your issue to the game's subforum as other folks there also lay the game and may be able to help you:

https://www.gog.com/forum/heroes_of_might_and_magic_series

Be sure to include what version of windows you;re using and if you;re playing the game via Galaxy. It's usually a good idea to list specifics and details when asking for assistance on any support forum.

You may also want to take a second and scan their subforum as I see a couple of threads already on dealing with crashes.

Hope this helps.

Like drmike said, check the game forum. If that doesn't help, contact GOG Support.

Check to see if you have Direct Play enabled.
Control Panel > Programs > Programs and Features > Turn Windows Features on or off, open Legacy Components> click Direct Play > Hit Ok

Some people seem to have had Windows updates sometimes turn this off on them.