Had a problem in the past few days, once I minimized worms from frontend or the game it is impossible to restore it.

I know some people have been having the same problems, after reinstalling everything found out that it works when you change the WA installation folder from "/Team 17/Worms Armageddon" to "/Team 17/WA" for instance.

No idea why or how, but it seems to fix it (for now). You might want to run the game in admin mode (right click>run as admin) and ensure the "Restore associations on open" checkbox is ticked in Advanced Options so that you can still open wa:// links.

You might want to run the game in admin mode (right click>run as admin)
I seem to remember Cybershadow saying that the game SHOULD NOT be run in admin mode, because it causes other problems. I may be wrong about this.

Had a problem in the past few days, once I minimized worms from frontend or the game it is impossible to restore it.

I know some people have been having the same problems, after reinstalling everything found out that it works when you change the WA installation folder from "/Team 17/Worms Armageddon" to "/Team 17/WA" for instance.

No idea why or how, but it seems to fix it (for now). You might want to run the game in admin mode (right click>run as admin) and ensure the "Restore associations on open" checkbox is ticked in Advanced Options so that you can still open wa:// links.

that's why you couldn't maximize - do not run WA as admin.
Read this (worms2d.info/Troubleshooting_FAQ#When_I_minimize_the_game.2C_I_ can.27t_restore_it)

Steps, this is not why I couldn't restore - I do not usually run the game with admin privileges.

Steps, this is not why I couldn't restore - I do not usually run the game with admin privileges.

well, admin privileges prevent restoring while in-game, not in frontend. Just an advice.
Then i don't know, sorry ;)

Steps, this is not why I couldn't restore - I do not usually run the game with admin privileges.

i had the same problem in Win7.
Check the properties of your icon (link to the executable). In Win7 is there (somehow) a checkbox for "run as admin". Disable the checkbox.