expired antivirus, cant renew as have a virus stopping internet connection.

Please be gentle with me, this is my first post and i am a complete technophobe!

I stupidly didnt renew my norton antivirus as i kept thinking i'll do it later :( you know later never comes! i turned pc on this morning to what i think is a worm/parasite/virus? (win32.zgfi.B) and it wont let me access the internet? i have tried turning off/on and also tried to install norton but to no avail...i am at my wits end.

 

Any advice greatly received.

 

Ketty x

 

i am on my lap top that can connect to internet so know it cant be my broadband connection.