salvage Old PC Salvage/part appraisal, what can I save from these PCs?

[MazeofPines]

Hey there!

 

I was rummaging around my attic and found some old PCs my family had stored there. I'm not too knowledgeable but I was wondering if someone with more expertise would be able to help me appraise them and see if there is anything worth Salvaging. There are three systems and they're pretty old so I don't expect to be able to salvage much out of them. After a quick glance, what I could see might be potentially worth saving are some HDDs, and maaaybe an i3? Could someone help me figure out what's worth saving and some potential uses for the salvaged pieces?

System 1:
Dell OptiPlex 790

Windows 7 Pro OA

Intel core i3

500GB HDD Western Digital (pictured)

 

System 2:

Dell XPS 420 

Windows Vista Intel core 2 Duo

x2 Western Digital 320GB HDD

 

There was a 3rd pc but I just grabbed the HDD out of that, it was the oldest of the three and didn't look promising but i'll attach a picture.
Also found an old Nvidia GPU (can't tell what model, picture attached)

TLDR: Found some old PCs, wondering if any of the parts are worth saving/selling? Need help appraising.
 

Any help at all would be greatly appreciated, I'm excited to learn something from you guys about this.
Regarding possible reuses, any suggestions are welcome! 
If we do figure out what I can save, I can then separate/repurpose those, but i'm wondering how best to dispose of the left over scrap?

Cheers!
 - Maze

 

[Firewrath9]

50$ for the i3 computer, and 20ish for the core 2 computer, idk about what else.

[MazeofPines]

That's not so bad for free PCs, I'm sort of eager to see if there's anything I can do with these parts, combine them to sort of frankenstein some parts together to make one of the systems better?

Any idea what model of Nvidia graphics card it is?

cheers!