Карты - Maps для Heroes 3

Lava, congratulations on registering!

Description of the computer

It doesn't matter at all and no one here needs it.

I can't open files on this computer

Why? Let's get into the details. If there are problems, ask, that's what the forum is for!
As far as I know, the original versions of "Heroes 3" (NOT the 2015 HD remake) work on all versions of Windows, but they work better on older versions, and on newer versions, they may require compatibility mode with Windows XP. On my laptop with Windows 7, the "Complete Collection" works perfectly. There may be problems on Windows 8 and 10.
If you can't install or run the game, you can try using the standalone SoD/WoG map editor from Black Phantom: https://drive.google.com/drive/folders/0B6mp_RaHLDRid3VCUlJILUdpemc
The editor works without installation - just unpack the archive into a separate folder and use it.

It's too lazy to count the map size in squares

Are you kidding? You don't have to count. In the editor, when creating a map, it is selected (by default - M, 72x72) and is always displayed in the lower right corner.