This has been an area of complaint for years and years. I've been building systems for over 15 years...and it was an issue back then and still is. Often, the coase's leads and the motherboard's connects don't match. I keep a small box of those little black plastic connectors for this very reason. Some boards use a 3 pin connector for the power LED. Some use 2, etc. As long as you have them connected and working, you should be fine. if not, you aren't going to hurt anything, but you may find your HDD LED doesn't work, or your reset switch doesn't work, etc.