2.5in External Harddrives not working

Hi! Can someone please help me? I pulled out the harddrive from my old Toshiba laptop and put it into a external harddrive case. The first time I plugged the harddrive into my mac, it mounted. For some reason, it doesn't mount anymore. Can someone please tell me how to fix it? The drive doesnt appear in disk utility either!

 

Is it only powered by the notebook or does it have an external power supply?

 

Does the drive spin up when you plug it in? you should be able to hear it. If it doesnt you should check the internal connections.

 

The harddrive spins up when I connect it. Also, it is powered by the notebook.

 

I'm having the same problem with my Toshiba hard drive that I took out and put into an enclosure. I have a hard time moving the files to another external hard drive... any help?

 

So...I log into windows xp (sp2) and I plugged my external in. It recognized it and it shows up in device manager but it doesn't show up in my computer. I've heard that these problems are because the external can't get a letter assigned to it. Computer Management runs fine but once I plug in the external, it freezes and I can't do anything. When I unplug the external, I see the drive appear for a brief second on the list of harddrives in computer management and then it disappears.

 

Anyone have ideas?

 

Can you give the external HDD some more power, either from another USB port or an external 5V PSU?

Whether an external 2.5" HDD will run off a single USB port depends on the computer (how generous it is a delivering at least 500mA through one USB port), the HDD (whether it uses more than 2.5W (5V x 500mA = 2.5W) when reading and writing) and the enclosure itself. In fact, many 2.5" HDDs use 2.5W or more when reading and writing. See the Tom's Hardware charts.

John

 

Mmm...my external harddrive was able to run on my computer from one USB for a long time. It only stopped working recently for some odd reason.