DO NOT WRITE ANYTHING ONTO THE DRIVE CONTAINING THE IMPORTANT DATA THAT YOU HAVE JUST ACCIDENTALLY DELETED!
Even data recovery software installations can spoil your sensitive data. If the data is vital to you, and you do not have another logical drive to install software to, take the whole hard drive out of your computer and plug it into another computer where data recovery software has already been installed.
DO NOT SAVE ONTO THE SAME DRIVE DATA THAT YOU HAVE LOCATED AND ARE TRYING TO RECOVER!
Attempting to restore deleted data to the drive letter containing the deleted data can result in part of the lost file being overwritten by part of the recovered file. Consequently the file will be lost for good, with recovery impossible. After you have recovered to another location, you can safely move the restored files back to their original location on the source drive.
See also: Frequently Asked Questions | Troubleshooting