I cant seem to get this game to get rid of the NO CD-ROM error at the beginning of the game. I want to play single player but I cant. i've checked the support section here on gog.com but it didn't work and I just cant figure out what to do.

It would help if you mentioned which Heroes game you refer to.

It's a HoMM 3 and its infamous crack-related problem. :-)
Solved many times already. Look or [url=http://www.gog.com/forum/heroes_of_might_and_magic_series/the_heroes_iii_the_shadow_of_death_cdrom_was_not_found]here for example.

I am asking since if you use HoMM2 Win verison and disable "Run as administrator", it will ask for CD-Rom as well ;)