That's to bad. If this is something that is only happening to that SSD, as in other secondary drives are still recognized, you can try the following:
Open the PC case and check the cables and connections to that SSD. If you have another SATA data cable, switch the current data cable with another.
If possible, temporarily remove all other drives except the OS drive from the PC. All you need to do is disconnect the power cables from the other drives.
After making note of any important BIOS settings, or saving them in a profile if your BIOS provides that feature, clear the BIOS/CMOS. Then start the PC and restore BIOS defaults and/or your personal settings. Don't forget to set the SATA mode to AHCI if you had that set previously. If you are reluctant to deal with the BIOS, when the PC is running, do a PC reset, with the Reset button on the PC case, and during the reboot go into the BIOS.
After any or all of this, look for the SSD in the BIOS again. If it's there, great, if not you can try removing it and trying it on another PC. It's usually best to use a SATA connection, but you could try USB if you have a SATA to USB external case.
Data recovery on a SSD is not something that can be done without specialized equipment. That is why it is so important to backup SSDs, since being a purely electronic device, data recovery is much more difficult. If an OS cannot see the SSD, a tool can't either.
I'm not aware of any tool that Samsung or anyone has, frankly.
I was going to mention any of the free Hex-editor programs, that read a drive's data in a raw state, but I don't see how they would work if Windows can't see the SSD. Even if it did work, that would be a terrible job, copying and pasting from the Hex editor, and not really knowing what is a file. I doubt that would work.
Consider, how could you bypass the electronics, when you must connect to the SSD through the electronics? Professional data forensics labs will actually remove the NAND chips, or somehow access them with the SSD opened up, and try to rebuild files from it, but that is very difficult.
I had similar experience to Alton's. I finally loaded the drive into an external enclosure. At first, nothing. Then I slid it hard into the connectors -- and it connected.
so tentative conclusion: the problem is mechanical, not electronic. I wonder if it's generic across the type or series?
If your Intel® SSD 520 Series is not recognized in the BIOS or as secondary drive even after trying the actions recommended in previous posts, we would advise to Contact Intel® Customer Support for further assistance.