Jedi Council Member
As for the linus video of a first-person build, I did not intend for it to be the main reference or something that you study closely. But it is fairly in-depth so I went in to look for the relevant part for you - installing the video card is usually one of the last things you do in a build, to keep free working space, so you'd have to watch the whole video just to catch the detail I was referring to.I'll study your video closely to discover whether there is a fail-safe method I could apply.
Linus starts finicking around the top PCI-e slot around 31:45, at exactly 32:10 he mentions the nub I was talking about (he calls it a 'tab'). This is the relevant part of the video, because that is the only manipulation that could interfere in the steps that concern you. Somebody who doesn't know could tug on the card and damage either it, the motherboard, or both, but you simply have to make sure to disengage it, the graphics card will half click out by itself.
Also, I said use your left hand, because that's an experience I could refer to easily and describe, but it depends on the size of your CPU cooler. I guess you can also come at it right hand thumb pointing down, going around and below the cooler to reach the tab. But at least now you'll know what to reach for.
Again, this is the only relevant second of that video. Push the tab back and the card half disengages.
All of that being said, the Jayztwocents' 'Serious issue has a simple fix' is the one to watch.