/u/mathsguy has it right. If it's a spinning hard drive, turn the computer off ASAP before it writes over the file. Either pull the hard drive, plug it into another computer and run a program like Recuva, or use a different computer to create a bootable CD or USB like Finnix that has recovery tools. Either way you'll need a second computer. It would probably be easier to just not use your computer until you get home and see if it's on your NAS.
Don't forget to backup your data!
TL;DR Use MemTest86+
There are two versions of MemTest86.
MemTest86 from PassMark and MemTest86+ forked from MemTest86 before PassMark managed it and it is free and open-source.
I used MemTest86+ because that is what I had on my Finnix USB stick (http://www.finnix.org).
The one key difference between the two is MemTest86 without the + is UEFI compatible. This just means it can run as a UEFI application instead of "booting" into MemTest86.
The only thing I know of personally that would come close would be Finnix. If it doesn't have the package/s you want they have a guide to make a remastered ISO.
It's been a huge help to me whenever I'm working on the library's server.