Windows 7: Mouse Pointer Disappears

Hi, Don't know whether anyone else has had this problem but my mouse pointer disappears in Media Center.
It never used to, this problem only started over the last few days.
I have a Roccat Kone mouse and I know that Windows 7 doesn't like it. I've had to download a fresh driver for each of the many builds I've installed over the last 6 months i.e. it won't install a stored driver.
Anyway. I can't think why this should have suddenly started. I've not installed anything new.
It makes Media Center virtually impossible to use for watching TV, using the guide etc.
Any ideas anyone, John