A THREAD FOR NEWCOMERS!

Two questions have arisen, and I haven't been able to find answers to them yet: 1) Heroes 3: Complete Collection, English version with HD mod, launches intermittently. Sometimes there's a black screen with the Heroes cursor, and that's it; it doesn't even reach the intro. Other times, it launches and works fine. What could be the problem? 2) I absolutely don't understand the logic behind how units with the same speed move. I remember a situation: I gathered all my skeletons into one stack, leaving the rest empty. I attacked upgraded zombies. They were also in one stack. The turn order was as follows: First round: 1 - My skeletons. I clicked "wait." 2 - The enemy zombies moved closer. 3 - My skeletons. I clicked "defend." Second round: 1 - The enemy zombies click "wait." How is this possible, and why is the computer going first now??? It gets even stranger. The zombies that decided to wait earlier than my skeletons go before them. I don't understand. 2 - My skeletons. I click "wait." 3 - The enemy zombies move and position themselves to be attacked by the skeletons. 4 - The skeletons defeat the zombies.