Subject- Sluggish tracking of AR-3000A after upgrading to -SERVICE PACK 2 for windows XP + adding the Microsoft patch for the new Daylight Saving Time.
Note- For months preceding this problem Scancat Gold SE and my AR-3000A worked OK while operating with Windows XP + Service Pack 1.
Troubleshooting - simple solution to problem
When you select and open a frequency file, DO NOT X OUT OF IT (or close it) leave it OPEN and minimize it. 
Stable operation returned after practicing this simple step.
George Bailey
Sherwood, Arkansas