Flash drive capacity issue

Hello everybody,

my problem goes like this, i have a 2 gig A-Data usb flash drive, but when you see it in the properties it shows that it's capacity was 7.9 gig. i tried to format this drive several times and a couple of times using low-level formatting method but still the capacity reports still the same 7.9gb. i can't save files more than a gig while it report a bigger free of space. i notice when i try low-level formatting it shows so many errors, what is the best i can do to restore this drive to its original state e.g. capacity. Is it a manifestation of virus? help please.....