DELL T1650 PC Case with Memory and CPU

This is what's left over from a PC migration. I used it for about 3 years after purchasing it used.
Includes case, CPU, 4GBx4 memory, and DVD drive. Power supply, storage, and graphics card are not included. Only what is shown in the images is included.

It was used until December last year and worked without any problems, but I migrated before I could test the DVD drive, so its operation is unconfirmed. The last time it was used was over half a year ago, but it was working fine then.
I believe the front and rear USB ports should be fine as I used about 8-9 ports daily.

There was one detached part, but I'm not sure which component it belongs to (see image).

Before listing, I blew off dust with an air duster and wiped it down with a wet cloth, cleaning intricate areas with cotton swabs. The circuit board and fans were only cleaned with an air duster. Some fine dust remains inside the equipment, on the circuit board, and in tight spaces where hands cannot reach.

There are some scratches on the sides and top of the case.

Case: Height 43.5 cm, Width 17.5 cm, Depth 36 cm
The case is quite sturdy and heavy, possibly weighing 7-8 kg.
CPU: Intel Xeon E3
Memory: DDR3 4GBx4
Front: USB 2.0x2, USB 3.0x2
Rear: USB 2.0x4, USB 3.0x2

Considering shipping costs, I do not plan to lower the price further. How about this for someone looking for parts or to build a PC based on this?

I am a PC beginner and don't know much, but I will answer questions as best as I can. If you would like to see more detailed images of any part, please comment and I will add them.