Error code OxC0070643

Hello Anna,
We understand how something like this can really try your patience.
To get your issue fixed, we request you to run AVG remover tool in your pc and then install AVG Antivirus back 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.

Thanks for the feedback, did a system restore dated back to 25/01 and everything is back to normal and working. Anna

AVG free edition was working fine until yesterday, then the problems started it showed that there was no protection and when I clicked on repair, the above code appeared.  I then tried to uninstall it, but that also failed. I then tried to download the free edition again, but thesame code appeared.  Please help.  I have no other virus protection.