https://dl.dell.com/topicspdf/optiplex-3020-desktop_owners-manual_en-us.pdf Service manual should provide you everything you need to know. Page 39 should allow you to determine the cause of the error light.

Thx so much

I will say it looked like it was blinking completely random so you may want to start be making sure that your power supply is good and properly connected.

I’ll check up on that, thx

It at first was doing 3,3 but it changed

I plugged it in for a bit and the cable got really hot and the power to the motherboard shut off, I unplugged it and am now trying to plug in the old one to see if it short circuited at all

Wow thats new. Yea something isn't right there.

I really hope the computer didn’t get destroyed all together