Have been asked to look at mates laptop its a Dell inspiron mini 10 running windows xp

It has no recovery partition no antivirus software loaded and hes addicted to ~~~~ so all hes done is downloaded anything with tits and viruses galore.
He has no recovery cds and the licence has come of the back
As there is no cd on these models and the hard drive is sealed in laptop case the only access is via usb
Is is possible to format and reinstall windows via usb
or a good virus scanner via usb as i would imagine the lap top is so currupted if i down loaded a virus scanner it would not touch it

chears Mosaicman