Erreur installation

Dear Alan,
Thanks for your anser.
What do you mean by AV in "3rd party AV".
The hard disk is partitioned in two:
C:
and
Q:
Q is not accessible.

I have the following error message at the end of AVG installation procedure with windows10 on new laptob
Erreur 0xC0070643
This is strange since this is a completely new computer with AVG (not free) downloaded from the official AVG web site.
Could you help me?

Annie, Does your new computer have a 3rd party AV installed & waiting to be activated?.
AVG Guru

Dear Alan,
Thanks for your anser.
What do you mean by AV in "3rd party AV".
The hard disk is partitioned in two:
C:
and
Q:
Q is not accessible.

Annie, Sometimes when you purchase a new computer there's also an AntiVirus prog provided that's waiting to be activated which can conflict with an installation of AVG.
AVG Guru

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.
To install AVG Antivirus please click on the following link http://files-download.avg.com/inst/mp/AVG_Antivirus_745.exe download and install the file. Also the license number has been sent to your registered email id.
Please feel free to contact us for any further assistance. Thank you.

Alan, may this conflict be due to Windows Defender?
If yes, what I have to do?
Do you want I send to you the "AVG journal file"?
Annie

Annie, Did you download & use the McAfee total removal tool (http://us.mcafee.com/apps/supporttools/mcpr/mcpr.asp)?. With Win 10 Windows Defender is classified as an AntiVirus prog.. which should be disabled during the AVG install process.
AVG Guru 

Hello Annie,
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 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.

Alan,
Yes I know that. There was MacFee installed but this anti-virus was uninstalled before installing AVG.
Annie