I recently got a Toshiba X300 5TB HDD and after installing it in my PC wouldn't turn on. I did my research and tried seeing what was wrong and after making sure everything was plugged in correctly I tried booting it up without my HDD and it worked. I turned on hot plug in the BIOS and then tried plugging the HDD in while my PC was running and my PC just shut off, keep in mind I was still in the BIOS while I did this (IDK if that was a good idea or not). So I'm coming to the conclusion that it might be my power supply, but I don't want to jump to conclusions and spend money that I don't need to. I honestly don't see what else it could be, but my ears are open to any suggestions, and If I do need a new power supply how much watts would I need?
SPECS
-i7 6700k
-Cerberus 1070ti
-ASUS H170 Pro Motherboard
-Adata DDR4 3000 2OZ 2x8GB
-Intel 660p NVMe PCIe M.2 512GB
-Seasonic M12 Bronze 620W
-I also run 3 monitors, (1) 144hz, (2) 60hz
SPECS
-i7 6700k
-Cerberus 1070ti
-ASUS H170 Pro Motherboard
-Adata DDR4 3000 2OZ 2x8GB
-Intel 660p NVMe PCIe M.2 512GB
-Seasonic M12 Bronze 620W
-I also run 3 monitors, (1) 144hz, (2) 60hz