Random starts for full scan - set on manual scan

I am having problems with Norton security randomly starting full scans. When conducting a full scan it slows the computer so much its almost unusable. I spoke with Tech support and after remotely accessing my computer they said to disable auto scan and do it manually. This was done and the computer restarted and confirmed that it was now manual scan.

Within 30 minutes it randomly started a full scan. I called tech support and they said it needed to be handled by a level 2 tech support and while waiting I got a recording to call back later and got disconnected; Great support!! NOT!!!!!!!!!!!!!!

Any ideas? I have had this problem for a while but it has progressively gotten more frequent with the random scans while using the computer. I need a solution or a refund of my subscription.

Thanks