So I just bought myself a new PC and wanted to transfer an old hard drive from my old PC into the new one. Whenever I connect the HDD to the PSU and try to turn the PC on, the RGB of the graphics card turns on, briefly, then turns off again. Nothing happens afterwards. I have no idea what is causing it since I'm quite sure I've plugged everything in correctly, but am very worried that there might be something wrong with the PSU. Can you guys help me troubleshoot it? I will need it running on the new PC soon, so I'm quite worried.
The new PC already has an M.2 SSD with Windows 10 installed.
As far as I know, the old HDD is not bootable.
Thanks in advance!