Hello Alex,
We understand how something like this can really try your patience.
To reinstall AVG Internet Security back in your pc, we request you to uninstall and reinstall AVG in your pc to get your issue fixed.
To run AVG remover tool for AVG Antivirus please follow the below steps :
Please click on the below link to download remover tool
http://aa-download.avg.com/filedir/util/AVG_Remover.exe
Accept the license agreement and then choose AVG Product and remove it.
NOTE: Once the AVG Remover Tool has done with its process. Please go to the drive where you installed this tool and look for a folder named as "AVG Remover" and I request you to delete it manually.
AVG along with PIA VPN have both stopped working and reinstalling AVG just fails!
Error code: 0xC0070643
Description: Event exec_finished
To install AVG Internet Security please click on the following link http://files-download.avg.com/inst/mp/AVG_Internet_Security_742.exe download and install the file. The license number has been sent to your registered email id.
Please feel free to contact us for any further assistance. Thank you.