Recently bought a 1tb usb powered samsung external hdd. After loading data and using it a couple of times when I connected and tried to access the data it was now showing that the folder was empty. When I went to properties and checked space and amount of data on it, its showing that all the amount of data before is still there! Tried everything, from scanning and checking for disc error but nothing is happening. My operating system is Windows 7 prof.

Since your disk is showing up with a drive letter, hopefully, check disk (chkdsk) can help:
http://www.wikihow.com/Fix-a-Cyclic-Redundancy-Check-Error
(this if for Windows XP) Google "checkdisk windows [your version]" if it doesn't translate well.

Falls are a huge cause in external hdd failure, though, so I wouldn't be surprised at all if the disk is beyond help. Try connecting to another computer (to see if the problem still occurrs) or another operating system (you can boot to a linux live cd) or, at least, use another USB drive on the computer you are connecting to.

Next step would be to *cross fingers* hope the external enclosure suffered damage, but that the actual drive did not. If you are comfortable doing it (likely voiding your warranty), disassemble your external enclosure and remove your SATA hdd. You can open your PC and connect it to your motherboard assuming you have an available SATA connection, SATA cable, and available SATA power hookup. Alternately, you can buy a 'kit' to connect a hdd to your pc via usb, which prevents you from having to open your PC. It is much more convenient if you can diagnose without purchasing 1-time use hardware, though.
(Google "sata to usb" -- i buy from NewEgg usually, cheapest with 4 stars)

You can try data recovery software, but they haven't been very helpful to me in the case of physical trauma to drive.

Data recovery outfits (expensive) may help if the information is not otherwise recoverable.

Good luck!

It sounds like the usb port on the drive itself is shot. You can actually take apart the case and pull just the harddrive out and use a hotswap usb harddrive reader and get to your files again

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try other usb port, or other computer and see whether the hdd is detected. If still not, try to go to device manager ( http://www.computerhope.com/issues/ch000833.htm ), and then assign a drive letter to the hdd. After that, try to access it from Computer, if not able to access it, format it (use quick format) and then use this hard drive data recovery program to recover your files.
http://www.asoftech.com/adr/

disconnect your WD ext HDD. and reboot your computer. then connect again. if still not showing. go to device manager (right click my computer then properties -- click device manager). expand by clickin "Disk drives" category here it will show all the hard drives installed in your computer including your WD ext HDD . if you see yellow sign on your external drive right click and remove then go to Action menu click on Scan for hardware. it should detect and install the driver again. if still the same or maybe its not on the list of Disk drives.. try to change another USB cable .. i hope this will help

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.

Make sure you are ready to recover your data ASAP. That means have your other hard drive installed and ready for data recovery.

If you are able to freeze your hard drive and begin the process and you are unable to get all your data, you can try freezing it again for a long period of time (24 hrs) try the process again. If you can not you might be out of luck.

Good Luck!

try other usb port, or other computer and see whether the hdd is detected. If still not, try to go to device manager ( http://www.computerhope.com/issues/ch000833.htm ), and then assign a drive letter to the hdd. After that, try to access it from Computer, if not able to access it, format it (use quick format) and then use this data recovery program to recover your files.
http://www.asoftech.com/adr/

Dear, What type of file system it is. FA16 supports only up to 4GB but FA32 and NTFS support more. For more info http://www.ntfs.com/ntfs_vs_fat.htm
And, please try to format the drive using FAT32 if its FA16 or NTFS and try.

try other usb port, or other computer and see whether the hdd is detected. If still not, try to go to device manager ( http://www.computerhope.com/issues/ch000833.htm ), and then assign a drive letter to the hdd. After that, try to access it from Computer, if not able to access it, format it (use quick format) and then use this program to recover your files.
http://www.asoftech.com/adr/

The problem could be the enclosure, not the drive.
I would take the drive out of the Calvary enclosure and install it in another one. Hopefully it will come up and you can access your data.