Mac Mini no longer working after Core 2 Duo upgrade.

I upgraded my 1.83GHz Core Duo Mac Mini to a T7200 Core 2 Duo and 2GB of RAM. The Wifi antenna was being annoying, so I only put it back together as far as reconnecting the internal frame (after reattaching the heatsync of course, wifi antenna is attached to airport card). Had to replace two of the nylon screws that broke. I connected it to a monitor and plugged in the power cord. It turns on, the fans run full blast and the sleep light comes on, but it never chimes. Nothing on the monitor either. The Mac worked before the upgrade. Please help!

EDIT: Please ignore the above text

Not sure what I did, but I got it to boot up just fine. However, the audio is not working and system profiler says No Built in audio. Why would this be?