Oscularia, I'm afraid that unfortunately Windows XP 64-bit is not now a supported operating system. Have a look @ this AVG article (http://avgread.me/1Ewajhi).
AVG Guru
I´ve been using AVG Free Antivirus for years (have to say thank you here), last updated was 2015 (from earlier versions) on Windows XP Professional 64x. For a clean installation I decided to uninstall it (plus used AVG Remover) and intall from zero AVG Free Antivirus 2016 but now im stuck on a "incompatible operatin system" message while trying to install.
AVG specifications are that Service Pack 3 is needed on Windows XP, but XP 64x does not have any SP3, that is for XP 86x.
I tried to install AVG Antivirus Free 2016 or 2015 from offline installers, like 200mb each instead of like 2mb internet setup file (AVG_Antivirus_Free_x64_693 and avg_free_x64_all_2015_ltst_221) but both ends on a step where it says incompatible system, so i disabled internet connection since I guess they are checking for last version. Finally I and can get 2015 to start installation, but it stops on some point saying internet connection is needed, no logic here since it is supposed to be an "offline" installer.
Im considering buying newer OS but that is not posible now for some specific working needs on a computer, so, untill then i´d like to get AVG working again like it was doing until some days ago.
Regards.
Oscularia, I'm afraid that unfortunately Windows XP 64-bit is not now a supported operating system. Have a look @ this AVG article (http://avgread.me/1Ewajhi).
AVG Guru
AVG Guru