SyncBack from www.2brightsparks.com is a backup system available in both 'Freeware' paid for versions, the paid version will backup 'open' or locked files allowing you to continue working whilst the backup continues in the background.
A real advantage SyncBack offers over a 'drag and copy' manual backup or even windows own ntbackup is that if an up to date copy of a file is already stored in the backup folder or drive, then it won't be re-copied, and the files may be stored individualy zipped.
This means that the backup drive, memory stick or a CD or DVD with a copy of the backup folder on it may be taken to another computer and 1 single file from the backup copied and opened without any special software.
7-zip from www.7-zip.org will compress and decompress archives in the ZIP format (newer windows operating systems include the ability to work with ZIP files).
The ZIP format is often used to compress a large number of files into on smaller file before storing it in a backup, uploading it to a website or sending in an email.
7-zip can also be used to exrtract files from a large number of archive formats including Tar, GZIP, RAR, CAB, ISO files.
PhotoRec from www.cgsecurity.org/wiki/PhotoRec will search a hard drive, CD/DVD, Memory Stick, or any other device that is seen by your computer as a hard drive (such as a camera) for photo, document and media files. As the program searches the drive sector by sector looking for files, even deleted files or files remaining on a drive after it has been formated can be recovered.
File fragmentation may mean that not all of the files are recovered completely, but with many computers using hard drives many times larger than needed for the data stored on them, fragmentation is less of a problem.
If it is the computers main hard drive that contains the 'lost' files, use of the computer should be avoided (as tempory files may over write the files you hope to recover). If possible, copy the PhotoRec software onto an external drive or memory stick big enough to hold the recovered files using another computer.
When ready, power up the computer with the external drive in place, open the 'My Computer' folder and then the external folder and run the program.