usb keyboard has gone mental, doing things without me

i am using a sony vaio laptop and use a USB saitek eclipse keyboard to play
my games on my tv.
all of a sudden without any warning.. (i had gone to make a cup of tea after
an uneventful mornings work)
my keyboard has got a mind of its own.
if it is plugged in, i get it typing random letters..
when i came back to it, i found 49 search screens open. nothing was in the
search though.
i wondered if it might be some kind of virus, but it doesn't seem to do
anything really harmful, and when i take the keyboard out the problems stop.
i tried the keyboard in my brothers computer and it behaves properly.
I think this is a software issue, but this uses woindows drivers so i can't
reinstall any drivers from the saitek website and if i try to reinstall from
windows, it just uses the drivers that are already there and so the problem
persists.
I don't know how i canoverwrite these drivers to see if that fixes it.