Technical issues when launching the game.

Everything seems to be fine. I just checked – I installed the game, everything seems normal, I click on MM9.exe, the screen goes black, and nothing happens! Only a reset helps.
The most interesting thing is that it used to work fine. There are no mechanical damages.

Oh, I initially misunderstood.
It turns out that Heroes is crashing, and I thought the computer wasn't turning on.

Of course, the problem is not with the hardware. It's about the game and system settings.
Checking for viruses is a must. Sometimes it helps. Sometimes, after removing the virus, the software still won't launch. However, there's nothing to worry about.
I would do the following:
1. Save all save games, custom maps, and other files.
2. Run an antivirus scan.
3. Run a check of the hard drive for bad blocks, file system errors, and other issues.
4. Uninstall the game.
5. Reinstall the game.
6. Copy all save games and everything else that you saved earlier.

If the software is pirated and has copy protection, especially if it's tied to a volume serial number, you need to restore that serial number. If there's some other protection, you'll have to find a workaround.