I'd forget the game for now.
First problem is to identify whether a hardware or software issue. By software I mean OS or some other software (such as the game).
1) If you shut off system and go into BIOS with mouse / keyboard connected can you manipulate menu items?
2) If so you have basic functionality of hardware. If Not, then you need to check if a BIOS setting has been disabled
or changed to prevent their use. e.g. turned off the USB where their attached. If NOT, and not usable, then
either the mouse, keyboard, or MOBO has gone bad. Try swapping out mouse / keyboard. Before I'd condemn
the MOBO, I'd shut everything down, and completely reset the MOBO by either pulling the battery, or using the
reset jumper, or both. THen see what happens.
3) If all the above works see if mouse keyboard work for other software. If so, then their are issue with that game
and your system and need to contact the game manufacturer or reinstall the software, if applicable.