I used my usb hard disk but I cannot access it

First try moving the device to a different USB port ,if that does not work then the disk has corrupt files or the disk has gone bad

you should formate the usb and then use some anti virus program to scan it;

Check if drive letter associated or a folder in MMC disk management

Hello! :)

Try other usb ports on your laptop. If this doesn't work, replace your usb cable.

An external storage-device has four major components:

* the USB cable

* the power-adapter

* the disk-drive inside the enclosure

* the USB-to-disk-drive adapter inside the enclosure.

One of these components has failed.

Try a different USB cable.

Try connecting to a different USB port on your computer.

Try connecting to a USB port on a different computer.

Take a "multi-meter" and measure both the voltage and amperage output from the AC adapter, and compare with the specifications on the label on the adapter.

Open the enclosure, and remove the disk-drive, and then connect it as a "slave" disk-drive in a desktop computer, to see if it works at all.

Purchase a new, compatible, disk-drive, and install it in the enclosure, to "revive" your external storage device.

Get the part-number and serial-number from the label on your disk-drive, and access the manufacturer's web-site, and use "check warranty status", to see if they will replace the device, at minimal cost to you.

There exist commercial "data recovery" services that can try to repair your device, just long-enough to rescue and copy your files. For example, see: https://services.seagate.com/index.aspx?lng=en-US for a "no data - no charge guarantee".

First thing to try is other usb devices as well as trying the drive in a different port. Preferably one away from the original to make it use a differeant hardware controller inside your computer. Also try unpluggin all usbs and rebooting a couple of times.

And try your drive in another computer to make sure it is working. if it isn't it may just be the enclosure electronics are the problem. If you have important stuff on it then you can try taking the drive out of that and putting it into a universal usb drive enclosure to get it up and running again.

If your laptop will give your WD a drive letter, you can run chkdsk (Check Disk) from the Run prompt to verify that the drive does not have damaged sectors. many times chkdsk will fix minor errors allowing you to access the drive again.
Click Start, Run CMD, enter, then type: X: (X being the drive letter of the Seagate) then type chkdsk /r and hit enter. If it completes 100% try accessing the drive again.
If you cannot acquire a drive Letter when you plug in the WD drive, try going to Disk Management and assigning a drive letter.
Click Start, then Right click on My Computer and click Manage, then click Disk Management. See if your WD drive shows up in the list. If it does, right click on the larger box on the right and see if it will allow you to assign a drive letter.

Another option you may have is taking the hard drive out of the WD enclosure and either connecting it as a secondary drive in a desktop PC, or installing it into another external enclsure USB device, and try again to access the drive.

If none of these options work, your last option is to contract a Disk Recovery Service to acquire your data. They are usually very expensive.

You can open the case, and access the harddrive inside it. I found there are videos explaining the process on youtube. You can also find some info on Google. You'd then need either a USB SATA adapter, or a desktop computer with a SATA port that's not already occupied. Search for: western digital passport open case

Try connecting it to another computer. If you can see your data then back it up etc.
After you have recovered your data connect it to your computer, from Disk Manager, remove the partition, recreate it again and then format the drive, hopefully your external drive will be operational again.
There is a possibility that the hard disk has died and you will have lost your data. If you are desparate, hard drive data recovery companies charge an arm and a leg to recover data from dead drives.

May be the USB drive is damged. Try connecting it to another machine. If it works then plug it in to the same port as you have installed it.