Hi Meg,
I've had the same issue...so I found a trick that has so far, worked pretty well. It's essentially a hard reset, wiping out everything (like waypoints, routes, etc) on the device, save for the pre-installed basemap.
To do it, hold the Page button, upwards on the click stick, and the power button. The device will power on and ask you if you want to reset. I did and have had much better performance.
I hope this helps
Tim, October 2007