I really appreciate your help, thank you.
I am not new to Avast - I am already registered and have been for the past year or so. When I right click the orange Avast Icon and then "Registration Information" it shows the current status as "registered" so therefore there is no "register now" box (as shown in the "how to register online" information). What I am seeking to do is renew my registration for a further 12 months.
In the meantime, I have downloaded the current version of Avast 5.0.677 onto my desktop, but when I have double clicked it to install, it is first wanting to uninstall the one that is already installed (which is also 5.0.677), but I am scared to do that as it will leave me online and unprotected. I hope I have explained clearly.