My sister has a 8520. When she uses the phone, the trackpad will freeze for 2-10 sec, work for 2-10 sec, freeze for 2-10 sec and so on. The phone is new and has over 60+ MB free space.
What OS versio it is running on ? If it is .509 or .592, you may face trackpad freezing problem. I had lot of trouble with .592.
Upgrade to .681 or latest .1036. These are the most stable OS versions. You will find easy instructions about upgrading the software in BB 101 lecture series.
Keep us posted with the progress.
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