Question Trouble rebuilding prebuilt system

[scrawletonxd]

I cleaned out this system because it was so old and thick with dirt but it's the most unusual pc I have ever seen, I can't figure out how to put it back together, the part that is giving me the most trouble is the heat sink, I have pictures here:

https://imgur.com/a/8r1meX4

View: https://m.imgur.com/gallery/8r1meX4

 

[Eximo]

Well, I see two posts on the cooler and four holes on the motherboard. Did you break posts getting it off?

I see what looks like clips to hold something on the cooler, anything supposed to go there?

It either clips in or screws in, you've focused on a lot of things that aren't strictly important in your pictures.

 

[scrawletonxd]

Well, I see two posts on the cooler and four holes on the motherboard. Did you break posts getting it off?

I see what looks like clips to hold something on the cooler, anything supposed to go there?

It either clips in or screws in, you've focused on a lot of things that aren't strictly important in your pictures.

Sorry I'm not exactly sure what I'm meant to be showing, I can't find anything resembling something I'm meant to clip on or similar

 

[Eximo]

I'm not sure either.

The bottom of the motherboard, the heatsink from several angles. Obviously the fan clips to the heatsink and it may be the other half of the mounting mechanism? Does the fan look like it has any posts that might go in the four large holes on the motherboard?

If you provide the model of the system you could look up ther service manual. Stock images of it, or look for replacement parts that might have diagrams of how it is to be installed.