Dell optiplex 790 unable to boot

I have a dell optiplex 790 DT with windows 10 and 2 ssd's so I just put a 3.5 inch HDD in to set up a RAID 0 with the ssd's after I turned off the computer and put the HDD in it came up with "no boot devices found" so I ran a diagnostic and it showed that there where 2 OS paths and that they both where good and all 3 drives where good I messed with legacy boot and turned off everything but the main ssd and it says "boot device failed"