Dell Dimension 4600c

I have a Dell Dimension 4600c that I'm working on.
The Northbridge heatsink came off. It clips on with two eye clip hooks that I think are solder to the motherboard.
I finally got the motherboard out (4 pictures on top) which is on a tray. I can not figure out how to get the motherboard off of the tray.. It's like it was made not to come off.
Any Ideas?

Update!
I finally got it guys.
What I had to do was put some pressure by pushing the ide connectors. It finally moved and I was able to get it out..
Ok guy's..
I got my soldering tools, including the helping hands. I used the helping hands to hold the uclip so I could get the excess solder off of it so I could get it into the holes on the motherboard. I used the desolder wick and it worked good. The uclip now fits in the holes on the Mb. Now for the soldering part. The pins on the uclip do not come out very far on the bottom of the moterboard, so there is not a lot to work with. I tinned my soldering iron and then very carefully heated the pins from the uclip, then I brought the solder to the pins and just put enough on. Not much radius room before I'd cover some traces, which I didn't want to do. Looks like I got more solder on the uclip then there is on the one that didn't come off. It looked good to me.. So I waited a while and the uclip seemed like it was attached very well to the motherboard.
Now I normally clean the heatsink, but the thermal pad was intact, so I just put it back on. Uclip is holding fine.
Now it took me for ever to get the motherboard out and only like 5 minutes to put the hole thing back together. Now the scary part! I hooked the monitor, keyboard, mouse and PS plug. Turned it on.. Oh no, what is this beeping noise and nothing on the monitor... Oh darn. A steady one beep pause one beep pause..
I forget about Dell's having those lcd diagnostic numbers on the back. I could have looked at it and then figured out what was wrong. I just unplugged everything reseated the ram, plugged it all back in and it's booting fine now.

I like to Thank all my friends from the www.podnutz.com forums. With out their help and support, I would not be posting this.