AVG Free should not be interfering. I use it and don't have any issues with WLM 9.
Did you go to add/remove programs and do the
repair of WLM?
I'd also suggest a scan using
Malwarebytes to rule out malware as the source of the problem. Be sure to check the boxes on the last installation screen to update the definitions before you launch the program.
Let me know how these and if the problem is still happening after a repair of WLM and a malware scan.