You need to have a external hard drive, a USB stick, or any other mass storage device that have enough space to save what you want to recover.
Undelete a file
These tricks require you to act quickly because the risks that those files are overwritten by other files and data increase with time.
Recover a file from a unbootable PC
You should start by
checking if your hard drive is defect. If that is the case, proceed with the next title instead. Otherwise, no matter what PC or file system you have on your PC, you can recover files with Ubuntu (soon).
Recover data from defect hard drive
Keep in mind that a defect hard drive can regress in a very short time. It is essential not to waste one minute while the hard drive is powered with any tricks that do not succeed.