Scan Failure to detect infection

My Windows 7 ver 6.1 was slowing and behaving oddly yey AVG scans repeatedly came up clear. Finally resorted to the MS security scan which instantly revealed widespread infection by - MISLEADiNG:Win32/Lodi
It was successfully removed but has left scars all over the place so that a Win7 re-install is required.
Are there significant gaps in AVG protection? Disappointing to pay for "pukka" software only to almost completely lose functionality.
JRW

Hello John,

We would like to clarify that AVG protection program will secure the device, if it is regularly updated.
We aren't sure whether the detected threat by MS security scan is a potential threat for your computer.
If you provide the screenshot of the threat detection result window of MS security scan, we will be able to check it.
You can post the screenshot here in your topic. Click on 'Answer' & then click on the 'Image' [mountain symbol] & follow the instructions.
Please check whether you have 19.8 version installed for AVG Internet Security. Click on "Menu–>About" from it to check the version.
Thank you.