AVG updated will not run Firefox or internet connected programs Win XP

Hello Ken,
I apologize for any inconvenience this may have caused. I would like to assure you that AVG 2017 version is fully compatible with Windows XP SP3. Was the issue resolved after you uninstalled AVG?

All updates to the OS are installed.
system

Just updated free version AVG; critical stop sound when executing any internet connecting program including Firefox, IE, Chrome, Thunderbird, Skype etc. Uninstalled and looked for issues on forum but all are old or not applicable OS. NO error message login as admin. Looked for private setting but none available in this version. I would buy the software if it ever worked right and support was continued on XP. If it ain't broke don't fix it. I am an IT pro retired.