|If you are confident that, for example, of the 2 wires you have connected to your power on switch, and of the pins on the motherboard they go to, |
(1) per previous posts, see if you can extract the wires - often a little flap on the metal can be pushed in such as with a pin, to pull the wire out...
(2) "break" the existing connector ==> Perhaps you can cut it apart and PRESERVE its ability to plug in, such as the (common, and mentioned above) needing to get rid of an unused "middle pin".
(3) if I were to do it, I might see about (a) extracting the wire "some way" (either removing from connector, or cutting, stripping, AND TINNING (hitting with a little solder and a soldering iron) to prevent the "tiny" pieces of stranded wire getting in the way, breaking, etc; (b) if you have "hook up" wire, you may find you have some that would fit over the motherboard pin, AND the (a) wire, and be a snug enough fit to make your own connector. If you're a "hobbyist" who has heat shrink lying around, you might be able to customize for a tight fit (tho I hesitate to suggest a heat gun on the mobo to shrink the connection.
(4) might you have ANY KIND of connector - say hacked from an old CDROM drive, etc, that would fit the mobo? If so, then run the wires from it and snip them, and splice the wires together. This gives you (a) solid connectors on each end and (b) an easy splice(*)
(*) Splicing 2 wires.
1. if possible, slip a piece of heat shrink over the wires, large enough for both (of one side) and long enough to more than overlap the offset connections. Alternate: Taping.,
2. if possible, slip SMALLER heat shrink over each lead of one end.
3. solder the first wire, then the second. If the small heat shrink move them both over the solder joints and shrink; then move the large one over BOTH and shrink.
The overlapped connections ensure "no chance" of touching, and while not too important for a power button (*** NOTE Because it is -- I'm assuming -- a SIGNAL wire, a "request power on/off", NOT a power wire). If it is REAL power such as splicing lamp cord, then this unequal length splice is more important.
Follow up if you need any additional assistance.
P.S. I once had a motherboard with indicators, and a case with totally unlabeled wires, and even though I had to do things like cut apart connectors, I was able to do it.