laptop dilemna

i just received a text message from my sister asking if i know somebody who can reformat her laptop, learned that it was infected by a virus that was sent through her email. now her unit is acting up like a spoiled brat! taking so much time before it opens a tab or something. but whats worst than everything else is her laptop memory that she can't seem to figure how it became almost full, she even made sure to erase everything to loosen up a bit whatever shes doing and opening, but nothing works. i guess the virus does it all. so tomorrow we will try to contact the technician we were referred to and hopefully he can fix the poor thing.