Finally found out that the old Cable doesn't work. The old Computer has way more ancient Hardware inside than I've expected and the Motherboard Cable seems to not be connected to the Power Supply Unit with a Plug but completely integrated into it (at least I think so. The Components inside take up so much Space that you can't even take a proper Look into it). Why does Stuff like that always need to happen when way too much Stuff is going on?
Can you send a Link to a Guide that explains how to do it? I think if I should already have the necessary Tools (my Father claims that only a Screwdriver is needed but he isn't really a smart Person ) I'll just try it before I need to wait a Eternity again for a Delivery to arriveYou can remove and reseat individual wires from those clips, takes a steady hand and good tools, I have done it myself a number of times, they should all be the same length though.