OK the following programme will find nothing however, it appears to reset a component somewhere within windows and stops the alerts
Could you download and run Kaspersky pure trial from here http://www.kaspersky.co.uk/free-trials/pure
This is similar to AVP but is win 8.1 compatible
It will offer to remove Avast skip that and set the Avast shields to off for one hour
Once Kaspersky has installed you will see this screen
https://dl.dropboxusercontent.com/u/73555776/kas1.JPG
Select scan and allow it to update
https://dl.dropboxusercontent.com/u/73555776/report.JPG
Once the scan has completed and it has removed any threats select report on the top right
Click detailed report and post that here.
It appears that this may well kill it, but I will need the report to determine what it is so that I can then remove it manually
https://dl.dropboxusercontent.com/u/73555776/detail.JPG