Inspiron 14z 5423 and windows 10

Ok I have an Inspiron 14z 5423 and had windows 10 installed on it. Dell never gave me a backup disk and well the drivers disks I did receive were for a latitude not a inspiron. At this point I realized that the 14z 5423 is not meant to have windows 10 on it, and runs sluggish on mine. I would like to find out how to get a windows 7 factor reset. I do think it is ridiculous that even though I have a Windows 7 code that I do not have a windows 7 disk. I paid over $500 for the machine.