windows xp does not recognize any new hardware

i am using the japanese version of windows xp; for the last few months, my
computer (Toshiba v5/410MPEW, only sold in Japan I think) doesn't manage to
correctly recognize new hardware.

For instance if I insert a USB key, it says "New Hardware Found", tells me
the name of the key, but then goes to a screen where it asks me if I want to
connect to Windows Update to find the correct driver. Which ever option I
choose, it doesn't seem to be able to find the correct driver.

Unfortunately I cannot use System Restore points as they do not go back far
enough.

Can anyone help? It's beginning to drive me nuts...