External USB Disk is installed but not visible under Mu Computer

Try plugging it in to a different computer.
If it still fails, then the problem either is:
* power-supply (most external drives that have a 3.5-inch disk-drive inside require a power-supply; most that have a 2-inch disk-drive inside draw power from the USB port),
* adapter inside the external case (convert USB interface to SATA interface of the disk-drive) is failing,
* disk-drive inside the external case is failing.

Your best hope is that the disk-drive is OK.
Remove it from inside the external case,
and attach it as a "slave" disk-drive inside some desktop computer, and copy the files.

Computer starts normally in windows with a windows that is installed on a hard disk on that copmuter. In other words - windows is installed on an internal hard disk of a computer A. If you get it out and put in a computer B it wont work.

To have the things work:
1. First should set in BIOS boot up options first boot device CD/DVD, second OTHER/USB/EXTERNAL, third HDD
2. Should boot up from a CD and install windows on an external hard disk (in your case your 3TB Toshiba external HD)
3. Set in BIOS boot up options first boot device OTHER/USB/EXTERNAL, second internal hard disk e.g. HDD0, HDD1

USB hard drive is a portable external storage device that works just like a conventional hard drive. The device is simply plugged into a USB port on your computer as you would connect a flash drive. Unlike a flash drive, however, a USB hard drive can store a much larger amount of data. If your computer will not recognize your USB hard drive, you can try troubleshooting steps to resolve the problem.

Plug one end of the USB cable into the port on your hard drive and plug the other end into the USB port of your computer. Ensure that both ends of the cable are connected securely. Open "My Computer" (Windows XP) or "Computer" (Windows Vista/7). The USB device should be listed as "removable disk" once it is plugged into the computer. If it is not listed among the available drives on your computer, proceed to the next step. Ensure that the data cable is working properly. Try another USB cable if you have one available. Disconnect all other USB devices from the computer as they may interfere with the operating system detecting the external hard drive. Reboot the computer if the USB hard drive is still not recognized. Plug the USB cable into another USB port and check to see if the device is detected. If you are using a USB hub, remove the device and plug the external hard drive directly into a USB port. If the computer still fails to recognize the device, the external hard drive itself may be experiencing a hardware problem. Check the status of the hard drive in the "Device Manager" window. Under Windows XP, right click "My Computer" and select "Device Manager." For Windows Vista and Windows 7, click the "Windows" button in the lower left corner of the screen, then type "Computer Management" in the search bar and press "Enter." Select "Device Manager" in the "Computer Management" window. In the Device Manager window, click the "+" sign that appears beside "Disk Drives." If the external drive is not listed, click "Other Devices" in the Device Manager window and see if an "Unknown Device" appears. The external hard drive may have been detected but the device is not working properly. If it is still under warranty, take the device to the computer store where it was purchased to have it repaired or replaced. Hope this helps.

b>

A USB hard drive is a portable external storage device that works just like a conventional hard drive.

The device is simply plugged into a USB port on your computer as you would connect a flash drive.

Unlike a flash drive, however, a USB hard drive can store a much larger amount of data.

If your computer will not recognize your USB hard drive, you can try troubleshooting steps to resolve the problem.

Plug one end of the USB cable into the port on your hard drive and plug the other end into the USB port of your computer. Ensure that both ends of the cable are connected securely.

Open "My Computer" (Windows XP) or "Computer" (Windows Vista/7).

The USB device should be listed as "removable disk" once it is plugged into the computer.

If it is not listed among the available drives on your computer, proceed to the next step.

Ensure that the data cable is working properly.

Try another USB cable if you have one available.

Disconnect all other USB devices from the computer as they may interfere with the operating system detecting the external hard drive.

Reboot the computer if the USB hard drive is still not recognized.

Plug the USB cable into another USB port and check to see if the device is detected.

If you are using a USB hub, remove the device and plug the external hard drive directly into a USB port.

If the computer still fails to recognize the device, the external hard drive itself may be experiencing a hardware problem.

Check the status of the hard drive in the "Device Manager" window. Under Windows XP, right click "My Computer" and select "Device Manager."

For Windows Vista and Windows 7, click the "Windows" button in the lower left corner of the screen, then type "Computer Management" in the search bar and press "Enter."

Select "Device Manager" in the "Computer Management" window. In the Device Manager window, click the "+" sign that appears beside "Disk Drives."

If the external drive is not listed, click "Other Devices" in the Device Manager window and see if an "Unknown Device" appears.

The external hard drive may have been detected but the device is not working properly.

If it is still under warranty, take the device to the computer store where it was purchased to have it repaired or replaced.

Hope this helps

Try this method it may work.
If you can boot up with the external USB hard drive on your Acer, then use a working computer and copy the Windows installation CD onto the external hard disk then connect the USB externak hard disk to the USB port on your Acer and boot up using the external hard drive.

Your laptop's usb port may not have enough power to keep the portable hard drive running.

You may require additional power to the portable hdd by using a usb cable with 2 usb connectors.
or use a USB port that is powered.

The external storage device has several major components:
* USB cable
* external power-supply
* disk-drive inside the enclosure
* USB-to-disk-drive adapter inside the enclosure.
Try a different USB cable.
Try a different USB port on your computer.
Try a USB port on a different computer.
Take a multi-meter, and measure the output voltage/amperage of the power-supply,
and compare with the specifications on the label of the power-supply.
Open the enclosure, and remove the disk-drive, and attach it as a "slave" drive in a desktop computer, to see if bypassing the USB-to-disk-drive adapter bypasses the problem.
Look at the label on the disk-drive, for manufacturer, product-number, serial-number, and manufacture date. Access the manufacturer's web-site, and use "check warranty status" to see if the warranty still is valid. If so, the drive can be replaced, at minimal cost to you.
Buy a new, compatible, disk-drive, and install it in the enclosure, to "revive" your external storage device.
Search online for a professional "data recovery service". For a significant fee, they can repair your disk-drive, just long-enough to copy your files to a new disk-drive. Seagate's web-site has an data-recovery offer: no charge if we cannot recover your files.

Unless it's windows 98 you don't need a driver. If your computer can't see it, it's probably broken. Try plugging it in to another computer and see if it can see it

I am assuming that you are using Windows XP and USB PORTS on both computers.

First, try to use a different USB PORT on the pc, just to rule out a bad one.

Another thing is that the external HDD may not connect to USB 1.1, only to 2.0 for the speed it needs. Check to see if the pc has USB ports on back of case, those are usually 2.0.

Third thing is to see if any other devices that are USB can connect to your pc. If not, you may want to load the USB DRIVERS back on the pc, as they may be corrupted.

Hope that helps.

plz check your usb port if other device read ...........then your external hard disk so error. or if ex hard ok...you install windows vista .