Question Fixed it. Why did this work....??

[Cowabunga]

My PC, on a recent startup, decided to stop outputting video. I knew the monitor and cable were fine. I opened up the case, and noticed there's an identical PCI-E cable as the one plugged into my graphics card. I unplugged the one in the card, plugged the other one in, and now it works fine. My question is, why? Im not very PC hardware savvy, and had a friend build the rig for me. I'm wondering if this is a sign of something being end if life?

 

[Dj0gany]

Psu make/model?