external hard drive goes missing

Hi,
I have 2 identical HP notebooks (xp sp2) and a 30 GB usb external hard drive. When i plug the drive into notebook1 i can see all 30GB fine (5 on F: and 25 on G: ). When I plug it into notebook2 the G:drive seems to disapear leaving me with only 5GB on the F: drive. I've tried it on a number of other machines but I only seem to get the problem on this one notebook. any ideas?

This might be because you have an existing device in the notebook already set to use the same drive letter. Have a look in the disk administrator snap-in under Computer Management to see if this is the case. If it is, just reassign the drive letter for the device and your external drive will magically reappear