Thanks for the reply Jack!
I tried removing three of the four RAM modules and it turned on briefly, then off again before anything could show up in the screen and after that it turned on, I heard the beep and it started loading windows but froze at that point, before shutting down by itself. Tried with other RAM modules and it's the same, no changes except for the fact that now I can hear the beep, but it turns on/off/on every time. I'm using a different computer right now and unfortunately it's quite old so I can't use it to test parts of the other one and I can't get the minidump either, as I can't load windows on my computer. I do have a different Motherboard though.
Also, I took everything apart, cleaned it and put it back together but that didn't change anything at all.
EDIT: after many attempts, I managed to get it working with three RAM modules, it turned on normally without reseting on its own, I'll see for how long it stays like that. I went into minidump but the folder is empty so I'm not sure where I can get the information you need.