Question Loose screws in graphics card

[matty.kemp]

So I have a gtx960 with a single fan on it. I was taking apart my gpu graphics card to dust the inside and reapply thermal paste and while taking the screws out I stupidly took out the screws on the opposite side of the fan on a black back plate besides the circuit board (have no picture available right now). Anyway I realised I didn't need to unscrew these so just left the plate on and screwed everything back together after I was finished. But the screws didn't screw in to anything and just like dropped into their slots apart from 2 of them and when I picked it up something was sliding around in there. I'm not sure if it's from that part exactly but I'm assuming so and one of the screws even fell out as I went to put it back in my pc. I'm unsure on what to do. Should I try turning it on and see if everything working or is it too risky? I also put all the screws in slightly slanted and was sliding the 2 parts of the card around a lot as I was trying to line them up (I'm a kid and trash at handywork) should I open it all up and start again? And if so do I have to reapply the thermal paste?
Also while opening it up the first time I found a loose spring and a bit of broken plastic in the inside. Is this a problem? ( I would believe it is but my pc has been making a rattling noise when I move it around and I believe it was from this meaning it has been working while the spring was loose)

Thanks in advance and sorry for the messy paragraph it's 5am and I'm on mobile

Edit: found this image on Google for reference. It's the same layout as my card but might not be the same idk https://images.app.goo.gl/Rfqfegx3pA7dAWj19

 

[matty.kemp]

I accidently unscrewed the screws in the back of my fan In my 960 while taking the card apart. Now the fan is sliding and the screws just drop out. Unsure on what to do