Appears on Device Manager but not on My Computer

I have a WD passport drive 160Gb which i use with my EEEpc and other file transfer between mine and other computers. The driver worked just fine. After a brief backup of a friend's laptop, for no obvious reasons, the device stopped appearing on My Computer. A quick glance at the Device manager showed that the device was there. The administrative tools does not recognize the driver so to give a Drive Letter. The disk LED lights up normaly and the plates are spining as they 're supposed to. Any ideas about this issue?
Note: the drive is powered normally and the usb ports i plug this puppy in are tested for that.