mouse/curser problems

I have had this problem for some time, the pointer randomly migrates to one or other of the corners or to the dock or the sides then slides to a corner or disappears for a few seconds before before reappearing, usually in the top left corner. As a leisure user this is only a minor annoyance to me. However my grandchildren play timed games/puzzles/exercises and the find this problem to be extremely frustrating. I think it may caused by a program that i have inadvertently downloaded. can anyone offer any advice? Thanks.

More description of the mouse type etc, and the mouse preferences please.

Apple Mighty Mouse usb as provided on purchase
mouse preferences on factory settings-sliders on mid points
universal access mouse settings-initial delay slider on 4th marker-max speed slider on medium-cursor size normal
Is this helpful?

dave43 said:

mouse preferences on factory settings-sliders on mid points ... universal access mouse settings-initial delay slider on 4th marker, max speed slider on medium-cursor size normal Is this helpful?

Click to expand...

Thank you. With one or two minor differences, that looks very much like my own TigerOS mouse settings, but I'm not using a mighty mouse.
Try this: http://www.youtube.com/watch?v=j0DH1R_GMQs ... and related links

If the mighty mouse continues to act up, you may wish to consider purchasing an alternative and much cheaper generic optical mouse. They work just fine with OS X.

Thanks for your advice. I've tried with an alternative but I'm still getting the same problem which makes me think the cause is rogue download rather than a hardware issue. Anyone any ideas?