Hopefully you got it fixed, just as an FYI, since moving to a 4k monitor I've had some occasional problems with my mouse cursor disappearing, usually in desktop sometimes in a game.  To get it back sometimes it works to go in your mouse settings (in Win7) and turn mouse trails on.  Put it on it's lowest setting if they annoy you.  However some games won't work with mouse trails on (like Civ5) and you have to turn them back off, but often toggling them on/off fixes the problem (worse case a reboot is needed).

In win 8 activate charms/settings/control panel/mouse then click on Pointer Options.