AVAST secure browser and antivirus will not uninstall

HI All,
im hoping to get some help with a windows 7 home pc that has recently had AVAST Antivirus free and the secure browser installed on it, as of two days ago most programs will not either open i.e outlook, word etc i notice in task manager avast secure browser running multiple times even when it wasn’t open. So i disabled the ‘self defence’ mode in Avast AV, things worked a little better after that but uninstall would not work even in safe mode and even the avastclear program doesn’t work. It opens and just says ‘starting’, and does nothing.
Any help would be amazing !!

thanks

Self Defense Mode protects Avast from being turned off or otherwise being changed by malware.