Recently built 3 Pro. When I went to power it up the screen flashes on and off and I can hear the hot end fans cycling on and off as well. I've gone through the power supply and opened the fans to see if there was an obvious issue because that's all I could find online as possible culprits. Was finally able to get it working but I'm not sure if I made a difference or if it was a fluke. Was able to print the dog. Went to power it up the next day and it is back to not working. Suggestions/ possible solutions?

Sorry if there is a post covering this but I couldn't find it using any language I could think to describe my issue.