CANT FACTORY RESET LATOP

First, my laptop is glitching out, taking up space for software that I have deleted. I have tried many things to fix this including first aid and disk utility but none of them work. Ok, I decided that I want to factory reset my laptop. I clicked the button and for some reason when asking for my Icloud password to sign out, it's not my correct email. my email has two 5's at the end like "55" but it shows up at "5" at the end. And my password for my normal account doesn't work. I try it multiple times, restarting my laptop but nothing works. It also says Authentication error 7003 but I think thats because I tried to do it too many times. Please let me know how I can reset my laptop.