Original post by: adlerpe ,
If both the keyboard and the trackpad are out, one possibility is a damaged [product|IF108-048|upper case cable]. It's a ribbon cable that attaches the trackpad to the logic board. Since the keyboard connects to the trackpad through a separate cable, both systems can be affected by a damaged cable. The power button working makes this less likely, since that button runs through the same cable; but it's possible that some traces are shorted out while others still work. In any case, a cable is the cheapest and easiest thing to replace. If it works, great; if not, you haven't thrown a lot of time/effort/money at the fix.