Installing new scsi SAS drive to my NTFS file system setup - Now my PC wont boot

:emotion-7:Can anyone help

I recently installed a scsi/SAS seagate drive to my Dell Precision t7500 PC which was running windows 10 64 bit. I had three ATA drives ie. disk 0, disk 1 and disk 2.

When I installed the SCSI/SAS drive it prompted me to format as NTFS or  GPT?. Not realising  I fomatted it as GPT (disk 3) and then used this drive to save my windows 10 system image and backup as well as storing my autocad software All was well for a short while then my pc would not boot?  

Can anyone help me resolve this as I need to use my pc for work!! 

THANKYOU!!!!

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