i have an external hard disk of toshiba which was working but my pc doesnt show it when i plug it in, wat may be the problem?

[Partiman Siwa]

searching for the driver

 

[lakerpt]

try and see in disk manager if the disk has a drive letter given to it or if it is initialized. (right click on "My computer" - select "manage" and look for disk manager.
if there is a partition on the disk, you can give it a drive letter