Hardware

You need to use the Safely Remove Option to dismount it before unplugging it or turning off the computer. You Should Never leave any external Drive plugged in 100% of the time as it's not designed for this and is not properly dismounted when you turn off the Computer as well as taking a Voltage Spike when you turn the computer on.

If you do not correctly plug & unplug the External Drives they fail because of numerous reasons but the most likely is that it's gets it's Partition Information Corrupted and the Master Boot Records become unreadable to the computer.

When this happens you can try the chkdsk /r option and see if that works but if it doesn't and you have Important Information on the drive that must be recovered you should send it to a Data Recovery Specialist and do Absolutely Nothing tot he drive. The more that you do the harder it's going to be to recover the data as well as making things considerably more expensive in the process.

However if it would only be nice to recover the data you can try one of the many Data Recovery programs available. A short list is here

http://tinyurl.com/273ay5

http://tinyurl.com/rmvrv

http://tinyurl.com/yvrsl

http://tinyurl.com/yyk8cm

http://tinyurl.com/382vm

http://tinyurl.com/ynwnel

http://tinyurl.com/nc4kx

http://tinyurl.com/2wox7l

http://tinyurl.com/374d8b

http://tinyurl.com/djw6u

http://tinyurl.com/f73se

http://tinyurl.com/8bd3f

http://tinyurl.com/afu2j

While the last 2 are from the same company they are very different products. Win Hex should only be considered foe use by someone who knows Hex Inside Out while Davory is a great cheap General Purpose Application.

Personally I prefer the On Track Option but it's anything but cheap. However because I use this type of software a lot it's paid for itself many times over by now, for a cheaper option Spin Rite from Gibson Research or Stella have both very good reputations by other TR members.

Col