I almost agree on throwing away a trackball mouse in this day and age-- but I have in-laws who still use one, so individual preference.

I assume you keep your machine well monitored/serviced by using such free software tools as:

Ccleaner [freeware and pretty good program at ccleaner dot com.]

Ad-aware

Spybot 

 and a good registry cleaner-- several freewares out there.

I mention these because they are pretty easy tools for even the non-pc savvy folks like my in-laws ! ;-)