DO NOT WRITE ANYTHING ONTO THE DRIVE CONTAINING YOUR IMPORTANT DATA THAT YOU HAVE JUST DELETED ACCIDENTALLY!
Even data recovery software installation could spoil your sensitive data. If the data is really important to you, and you do not have another logical drive to install software to, take whole hard drive out of the computer and plug into another computer where data recovery software has been already installed.
DO NOT SAVE ONTO THE SAME DRIVE DATA THAT YOU FOUND AND TRYING TO RECOVER!
While saving recovered data onto the same drive where sensitive data was located, you can intrude in process of recovering by overwriting table records for this and other deleted entries. It's better to save data onto another logical, removable, network or floppy drive.
CREATE DISK IMAGE IF YOU HAVE EXTRA HARD DRIVE, OR OTHER LOGICAL DRIVES ARE BIG ENOUGH!
Disk Image is a mirror of your logical drive that is stored in one file. This can be useful when you want to backup the contents of the whole drive, and restore it or work with it later. Before you start recovering the deleted files, it may be a good idea to create a Disk Image for this drive, if you have enough space at another drive. Why? Because if you do something wrong while recovering the files (for example, recovering them onto the same drive could destroy their contents), you still will be able to recover these deleted files and folders from the Disk Image that you have wisely created.