i tried 5 it made my comp slow way down to not even 1/2 the speed and made it freeze when ever opening file or browser or anything at all
i went back to 4.8 the new stuff just not worth it
i only want to be safe not all the extra stuff
only option i need is delete virus when found 
Try uninstalling 4.8 and installing v5. See if any changes happen.
hey u should actually do a clean install.
v5 has indeed a greater impact on system performance than v4.8, but v5 still runs ok. just uninstall 4.8, reboot and install v5. things should be ok.