Nothing happens when I enter the serial code in "Profile".

in that case the next time you run the game and this happens, could you send me the files found in

my documents\ my games \ gratuitoustankbattles\debug

to cliff AT positech DOT co DOT uk

That might shed some light on it.

E-mail sent.

It’s working, now.

The problem was related to the username in the profile not syncing up with the serial key. It was solved by me simply creating a whole new profile, as advised by Cliff Harris. Lost my progress, of course, but the game is now working again, so I’m happy.

Note that I still need to run the game windowed because if I go fullscreen, the game will run in high-speed as described earlier.

Many thanks for the help, by the way.