you don't mention which version you're running, but to install anti-virus software you'll need to be logged into Windows with administrator priviledges.
In Win XP you can resolve the problem by going to Control panel and clicking on 'User accounts'.
OnePlus 5T review: Hands-on
Illustrator Andrés Lozano on his improv line work, brazen use of colours & hand sketching
iPhone X review
Comment envoyer gratuitement des gros fichiers ?