I have a Toshiba M5 and the mouse intermittently trails across the screen for no apparent reason. If you search the Toshiba support site it’ll tell you that this is the mouse recalibrating itself and you should let it do it’s thing. (Don’t attempt to fight it.) However, for some folks (like me) the mouse/cursor basically has a mind of it’s own, and it can drive you crazy. I mean, really, have you tried surfing the internet without a mouse lately?!
As it turns out, the “trailing mouse” issue is typically one of two things. That is, either the keyboard or the track pad going bad. Apparently it’s a cheaper repair to replace the keyboard first, and then you might try the track pad.
What if you don’t have the time or resources to get it fixed? The “band-aid” is to disable the trackball. Make sure you have the mouse drivers properly installed (from the Toshiba website). And then go into the Control Panel Mouse Settings (Advanced settings) to disable the “nipple”. This should fix the problem of the crazy mouse!