Please help me understand this more clearly

also noted in the first article linked: "AVG can be installed on Windows XP (SP2 and newer)" - SP3 is "newer" is it not?

The notification seems to indicate that XP Professional SP3 is not supported, as does the User Manual. I seem to recall hearing that Microsoft no longer supports any edition of XP, so be prepared for more outrages in the future. You might have liked Windows 7, but  now Windows 10 is already in technical preview (which however is not yet supported by AVG). You mentioned Panda, I believe it only supports 32-bit versions of XP. Like the Guru says, maybe you just downloaded the wrong installer file?

This image is not available because: You don’t have the privileges to see it, or it has been removed from the system

OK Gary, In the end of the day AVG 2015 Free should work with WinXP SP3. Since you cannot find any AV that will load could it be an issue with the rebuild?.
AVG Guru

> "could it be an issue with the rebuild"?

Good question! I have not seen, anywhere, whether or not an OS must  be 'registered' or 'activated' by Microsoft in order for an AV package to be installed. This machine has yet to be certifried. I have original W95 & W98 disks and 2 XP (home) installation media and COAs from defunct machines ncluding the one on the side of this Lenovo.  Just have not done that yet.

I have just acquired that file - if I do not return, assume the worst

Gary, WinXP & AVG… Have a look @ this article (https://support.avg.com/SupportArticleView?urlname=AVG-support-for-Windows-XP).
AVG Guru

Gary, Try the 32bit install file. There's nothing to be lost!
AVG Guru

also noted in the first article linked: "AVG can be installed on Windows XP (SP2 and newer)" - SP3 is "newer" is it not?

The notification seems to indicate that XP Professional SP3 is not supported, as does the User Manual. I seem to recall hearing that Microsoft no longer supports any edition of XP, so be prepared for more outrages in the future. You might have liked Windows 7, but  now Windows 10 is already in technical preview (which however is not yet supported by AVG). You mentioned Panda, I believe it only supports 32-bit versions of XP. Like the Guru says, maybe you just downloaded the wrong installer file?