If you are experiencing trouble accessing your data, turn off the computer or unplug the hard drive and contact a professional ASAP. Many times, a drive wiith mechanical failure can be recovered easily for a short time after initial symptoms appear. Afterwards, it can be ten times as expensive.
We have a dedicated data recovery suite to provide the best possible service for your troubled storage media. We are also partners with DriveSavers, in the event that local recovery is not an option.