take the power led, put a small wire into one end, slide the other over the led connector, touch the wire to the other ideled connector and see if it light up when using hard drive or cd-rom,turn it around if still doesn't work. if nothing help then it could be a screwed connector. No biggie, just one less light, only visual loss (I don't even look at the led).
the wire needed because the power led connector 1 bigger than the drive led connector
if I'm not clear then let me know, will take pictures.
<font color=red>We born naked and screaming, then it gets worse.</font color=red>