Happens to every 10 games or so.

Graphics: ATI 4200HD Mobility

Processor: AMD Triplecore Mobile

This happened to me today (and has happened many times before); I will experiment in Dominion and try to reproduce the effect so that it may be copied.

I have not had the problem of my cursor disappearing but I have had problems with what seems to be a keybind. (I don't know) Sometimes when I am playing on dominion every time I press R the cursor is recentered to the middle of the screen. Extremely annoying when I am playing Akali who uses her ult rather frequently.

Is this only me? The only thing that seems to fix it is restarting the computer.

nope, mouse still dissapeared with "borderless" settings.

showing mouse trails is a quick, temporary solution though. have your mouse properties open when you play and just alt+tab and check "show pointer trails" when your pointer dissapears.