So, I've had a toshiba 2.5" SATA 250 GB internal HD for a while now. I got it from an old toshiba laptop. I finally got an enclosure for it, and I plugged it in. windows made the sound it makes when you plug something in, and in device manager the usb port said a usb mass storage device was plugged in, but it didn't show up in my computer, nor did it show up in disk management. I searched the net for hours trying to find the problem, reading about how you might need to assign it a letter in disk management, and other more "grim" outlooks on how it might be dead. I listened to it closely, and heard it making very VERY soft ticking noises at a regular rate. I immediately thought the worst, and came to the conclusion that it was dead. The next day, I decided to take it into school with me, as my teacher was pretty smart when it came to computers, and maybe she could provide the tiniest shred of hope. She asked me to plug it into one of the school's desktops. I plugged it in and...it began running like normal. It showed up on my computer, and showed the correct disk size, as well as a document I'd put on there long ago. I couldn't believe it! When I got home, I plugged it into my computer, but surprisingly encountered the same problem. I decided to do a bit of experimenting, and I started plugging it into various computers we had around the house, and lined up all the facts I had: It didn't work on my laptop. (runs windows 7 home premium) It DID work on my mom's laptop. (also runs windows 7 home premium) It didn't work on my old desktop. (runs windows xp home edition, but I don't trust it. It's been acting very weird lately) It DID work on my school's desktop. (runs windows 7 enterprise) It DID work on my sister's laptop. (runs windows 7 home premium) I was stumped, to say the least. Can any of you tell me WHAT THE HECK IS GOING ON?!?!?! The strongest lead I have is that it might not be working correctly on my computer because the usb ports can't provide enough power to mount it. But if my laptop can't mount it, why should my mom's or my sisters be able to? Please provide any other theories you may think are plausible too!