In order to recover a deleted file:
You need to have some knowledge about your system.
Spare disk space. If not on your system, then on another system that you can hook the original disk up to. You'll need at least *220%* of the free disk space of the file system that the file was lost in. The 220% is needed by:
100% = the unallocated blocks that you'll be recovering
120% = roughly the space lazarus will consume. It'll be at least 100% + some additional space.
At least a few hours of time (much of this will not be you doing any work, but the programs involved are slow).