Avast 4.8 vs 5.o

During a recent update of Avast 4.8, which was set for automatic updates I think I may have inadvertently Upgraded to the 5.0 version which will not activate whatsoever and uninstalling and re-installing it doesn't work either. I feel vulnerable without something on my system. Do I remove the 5.0 and try to re-install 4.8. I also have Malware bytes which will no longer access the website for updates as well.
Any suggestions, Please.