external hard drive not showing up in finder, disk utility, or system profiler.

hello,
first, i would like to apologize for being a noob both in terms of mac and using forums. i am trying to use my external hdd, but it is not showing up in finder, disk utility, or system profiler. the device showed up yesterday, but after formatting the hdd, it has disappeared. i have tried both usb ports as well as a different usb cable. i am currently running os x 10.4.11 and the external drive is a western digital (don't know the product number, it was given to me by a friend.)

Can you feel the drive spinning at all? It's possible it may have failed either mechanically or electronically. Try plugging it into another machine, Mac or PC to see if it shows up there.

Problem caused by WD drivers

Hey, i just joined this thread because i wasn't able to find a solution anywhere. I also have a problem seeing disks. The problem only seems to apply to USB external hard drives. The hard drives are perfectly fine in every way, they just don't get mounted. The show up in the 'USB Device Tree' of System Profiler, but that's it. They can not be re-formatted or repaired by osx, because they don't even show up in diskutil (the CL version of Disk Utility). The problem started right after i installed the some WD drivers and before that they were completely fine, so i know that's the cause. Anybody know of a solution aside from reinstalling?

Why can't you remove the WD drivers? Also, it would help if you would tell us which Mac you have and what version of OS X you're running.

And be aware if you have a PowerPC Mac, it will not boot from an external via USB.