Question My new SSD is not booting properly

[Dogedeity]

A few days ago I got a W.D. 2.5 inch SSD. After having a lot of problems replacing my hard drive with it, I cloned my hard drive onto the SSD, then installed Windows 10 via a USB onto a separate, empty partition. I booted my PC on my old hard drive, and merged the SSD partitions. Then I disconnected all other storage devices from my PC except for the SSD. It now boots, but it's stuck on a black screen with a basic loading circle spiraling for a while until the computer automatically shuts off or goes into sleep mode or something. How can I fix this?

 

[rgd1101]

can't just merge partition with data / os
fresh install the os. reinstall the app

 

[Dogedeity]

can't just merge partition with data / os
fresh install the os. reinstall the app

Ok, so after I reinstall the OS, how do I access my old files from the previous drive? Because when I had the cloned stuff and the OS in two separate partitions, it was unclear how I could access the cloned files on the data partition.

 

[rgd1101]

it will show up as different drive. e.g. drive c drive d