Thanks for you help schmidthouse,
look forward to seeing what shows up on your Windows Task Manager when you open OE.
If your CPU usage creeps up to 50% while OE is running, try killing/select Avast for 10 mins and then immediately put 'All Shields back on again to see
what happens to you CPU usage. Amazing how mine just totally calms down.

BTW,
Do you know where I might find “Application Rules page” that is mentioned in AVAST’s Tools-Firewall-Application Rules- Configure?