The Cap in question is on the top left (in picture) the the 2nd cap up from the ATA100 IDE connector and above the cap next to that little heatsink.
This cap fell off my logic board several months ago. I realized today that this location is where that cap goes. What does it do? Could it be the cause of no DVI Video? Could it be the reason my AirPort Extreme Died? Should I reattach it?