William...
Let's start from the beginning as it were...
1. At this moment are you communicating here on Tom's forum using the PC that's having the problem(s) you describe?
2. Your present boot drive - the one you describle as a "460GB Eco3 SSD" - that's a Mushkin 480 GB (not a 460 GB) ECO3 model - isn't it?
3. Up to recently the system booted without incident and functioned without problems using that boot drive, right? If that was NOT the case, read no further. Capiche?
4. Now you've purchased a Samsung EVO 850 500 GB SSD that you plan to utilize as your new boot drive. So the obvious plan-of-action is to clone the contents of your present boot drive to the new Samsung SSD. (We'll assume the Samsung is non-defective.)
5. We'll further assume you're working with a desktop PC. (Always indicate the type of system you're working with when raising a problem similar to the one you've raised, together with the make/model of the motherboard or the make/model of the OEM PC that's involved). Capiche?
6. So, all things considered a simple disk-to-disk cloning ("data-migration") undertaking is called for. Should be a straightforward operation.
7. Presumably you will be using the Samsung Data Migration program since the Samsung SSD will be the recipient of the clone.
8. After installing the SDM program and with the the Samsung internally-connected in the system to one of the SATA connectors (ports), use the SDM program to carry out the disk-cloning operation. It should be a cut & dried operation. You don't have to fiddle with the Samsung SSD in any way PRIOR to the disk-cloning operation. There's NO NEED for a "Secure Erase"; there's NO NEED for initializing, partitioning, formatting the SSD. A "virgin" Samsung SSD as the destination drive is fine & dandy. Capiche?
9. After (hopefully) successfully completing the disk-cloning operation and shutting down the PC, IMMEDIATELY DISCONNECT the source drive (your Mushkin SSD) from the system and boot the system with ONLY the Samsung drive connected.
10. Assuming a successful boot to the OS and the SSD functions without probems, shut down the PC. At this point it's generally a good idea (although not vital) to connect your new boot drive to the motherboard's first SATA connector (usually designated SATA 0 or SATA 1).
11. You might want to check your BIOS to ensure the Samsung is first in boot order priority.
12. Now you can connect your "old" Mushkin SSD as a secondary drive and utilize it as you see fit.
13. After working with the new SSD for a while to determine all is well, then you can manipulate any of your files on the secondary drive, i.e., the Mushkin SSD.
Good luck.