Hello Neil,
We regret the inconvenience caused. We would request you to remove installed AVG program with including traces from your system using AVG Remover tool and then try to reinstall AVG Free.
Note: If you have installed any other conflicting programs like AVAST,NORTON, McAfee or KASPERSKY means please try to uninstall it.
Once you have uninstalled from your system,try to follow the steps which mentioned below.
Remover and Download
1) To download AVG remover tool, please click on this link: http://aa-download.avg.com/filedir/util/AVG_Remover.exe
2) Run the downloaded file and follow the onscreen instructions.
3) Restart your PC when the restart option is displayed on the remover tool screen.
NOTE: Once you have logged into your PC after the restart, please go to C:\ drive and delete the "AVG REMOVER" folder manually.
My copy of AVG Antivirus free is massively broken and cannot be removed or repaired. Currently, the Identity Protection and Resident Shield functions are disabled and cannot be reactivated, and when I perform a scan it just completes instantly, having not actually scanned anything.
When I try to repair the program I get the error code 0xE0010002 [Invalid Parameter Specified], and when I try to uninstall it I get 0xC0070643 [General Error (0x0643)].
The most concerning part is that Windows Defender is also non-active and fails to update, making me believe there is something on my system trying to supress anti-virus software.
Please help me 
(Running Windows 10)
That sorted it, thanks.
Hello Neil,
We are happy to know that the issue is resolved. We really appreciate your patience and co-operation. If you still have any query regarding AVG, you can always contact us.
Thank you.
To download the AVG Free , please click on this link: http://www.avg.com/us-en/avg-antivirus-free .
Please feel free to contact us if you need any assistance. Thank you.
Hello Neil,
We regret the inconvenience caused. We would request you to remove installed AVG program with including traces from your system using AVG Remover tool and then try to reinstall AVG Free.
Note: If you have installed any other conflicting programs like AVAST,NORTON, McAfee or KASPERSKY means please try to uninstall it.
Once you have uninstalled from your system,try to follow the steps which mentioned below.
Remover and Download
1) To download AVG remover tool, please click on this link: http://aa-download.avg.com/filedir/util/AVG_Remover.exe
2) Run the downloaded file and follow the onscreen instructions.
3) Restart your PC when the restart option is displayed on the remover tool screen.
NOTE: Once you have logged into your PC after the restart, please go to C:\ drive and delete the "AVG REMOVER" folder manually.