Seems like AVG Cloudcare with the AVG 2015 component (CloudCare version currently showing as v3.3.1) sometimes gets stuck on an update. It may just be for non-admin domain users, I haven't been able to confirm that for certain.
The user gets prompted every day for a Restart, which then nags hourly if they click postpone. Restarting and logging in as admin doesn't clear the problem - it repeats again the following day.
The more tedious option, if that doesn't fix the warning, is to uninstall and reinstall. After using the Uninstall from Control Panel > Programs and Features, do a reboot if required. Then run the AVG 2015 Remover program, that can be downloaded from AVG's utilities website here: http://www.avg.com/gb-en/utilities
Reboot, check there are no AVG folders left in C:\USERS\username\APPDATA or in Program Files or Program Files (x86) - and then reinstall. That definitely clears the problem !