Is there a way to connect an MSATA SSD to a 6Gb/s SATA slot?


Oct 27, 2015
I bought a Lenovo Flex 5 with a 7th Gen Intel Core i5 processor; 6GB of RAM a 1TB (slim) HDD. I bought it at Office Depot, where it didn't specify the drive was not SSD but HDD. Needless to say, the machine is almost unuseably slow.
I still have a 1TB MSATA SSD lying here from an older notebook and was wondering if there is any way to build that onto the SATA slot. The specs say it’s SATA 6.0Gb/s, 2.5" wide, 7mm high.
Alternatively, there is also an empty M.2 SSD / PCIe 3.0 x 4 slot on the mobo that is used in other configurations of the same notebook. Tech support told me it IS active, so I should be able to put an M.2 SSD in there. But that’d be an extra expense of course.
So my questions:
1. Am I correct is assuming that my MSATA SSD will not work in the M.2 PCIe slot, even though they’re both presumably PCIe?
2. Would it be possible to fit an MSATA SSD into that slim HDD slot – presumably through some adaptor? If so, would that be as fast as through a ‘normal’ MSATA connector
3. What would you recommend I do – especially since I still have this (much faster) MSATA drive still lying around.