Mouse loses settings

I have Win XP Pro, and a MS wireless laser mouse 6000.

I previously had a MS trackball, and they both have the same problem.

I set certain buttons to have certain functions in particular programs

(Autocad and Quickbooks). The one I use the most is setting a button to

perform "Enter".

After the computer has been on awhile, doing various things, the enter

function quits working.

If I reboot, it will then work fine for awhile. This is irritating.

Anyone know how to make this more reliable?

GC