Hi!
I just purchased Heroes 3, and was ready to play. When I started the game, it said I had to insert CD.. I bought it here online, so it is hard too insert a CD that I don't got. How can resolve this problem?
Tried to read all the manuals and start guide, but did not find the answer there..

Regards
Topper

Best guess is an installation problem, have a look here:
http://www.gog.com/forum/heroes_of_might_and_magic_series/the_heroes_iii_the_shadow_of_death_cdrom_was_not_found

Do you have any non-gog version installed? In that case, first uninstall the gog game, then the other version of HoMM3, and then install the gog game again as administrator.

It's been reported that even if you used to have a non-GOG version installed a long time ago, the registry settings left behind by that version will cause the problem you're seeing. So, as suggested, uninstall the GOG version, uninstall any non-GOG version, then use regedit to clean out any old HOMM3 registry settings. Finally, reinstall the GOG version.