HDD is dying and I cant make a system image

A few days ago, my computer has started to run as slow as it has ever been. It takes about a 10+ second delay to merely open a window(varies). I figured it was the hard drive and I ran CrystalDiskInfo and it told me Caution. I am not 100% sure it is my HDD but I can't imagine it is anything else. I have an unused SSD(Samsung 860 EVO 500GB SATA 6GB/s) and an external Seagate 1tb harddrive. I can only hook up one hard drive at a time because I only have the cables for one. I have been trying to put a system image onto the external hard drive and then put it on the SSD. I am not sure how this will be possible with being able to plug in only one hard drive at a time but right now I am more concerned about getting a system image finished. Please note that every scan i perform will take hours due to the speed it is at right now. Every system image takes about 8+ hours and it always fails. My issues include but are not limited to: 0x80070002, 0x8007045d, 0x80780119