Guys, please help! I have a licensed version of the game. I was enjoying it. There were no lags, and suddenly, in the second mission as the Necromancer, the game stopped working. It doesn't even launch; it crashes. As soon as I start it, the game's splash screen appears (like during a normal launch), but before it even loads the menu, it crashes without explaining why. Patches don't help. Reinstalling the game doesn't help either. According to the system requirements, my computer is three times more powerful; I don't know what to do. Please help!

Hmm. Do you have "Hammers of Fate" installed? And did you happen to download a map called "Heroes: Director's Cut"? The thing is, this map is a mod that adds several Easter eggs to the original game, which slows down the game's launch, especially at that splash screen. If you press any button, the game crashes. I can't think of any other possibilities. But there's another solution: maybe your save files are corrupted. If you don't mind losing your progress, try deleting all your save files (My Documents/My Games/Heroes of Might and Magic 5/Profiles/{your profile name}/Saves). You can also delete the save files named save1.sav, save2.sav, etc., and replace the campaign.sav file with another one (you can find someone else's "campaign" on a forum, but if you need it, I can send you mine). But if the problems started after completing a specific mission, simply deleting the campaign file should help.

When I go to Ubi to play a simple game, I get the following error: 0.2.0. It says that the client's game database checksum does not match the server's database checksum. My version is 3.1. What should I do?

The first thing that comes to mind is, of course, the game version. Does the person you're going to play with also have version 3.1? If so, here are some other possible solutions:
a) You have mods installed. Just delete them;
b) You're trying to play online on a map that only you have (you made it yourself in the editor, or you downloaded it from the internet). Choose a map that was made by the developers;
c) One of the maps you downloaded has a mod embedded in it. Consider this to be option a). Delete that map (if you don't know which one, copy all of them to another folder and delete them from the Maps folder).
I don't have any other ideas.