Forgot - Removal Provedure.
I am assuming you mean the Keyboard and not the keys as I am not sure about the keys.
After you have pressed the tabs (thereby releasing them) the keyboard should "pop up". After all four...
You should find the tabs located above the following keys:
* on the Num Pad
Press them inward (toward the screen) with a blunt object like a chop stick or very dull flat blade screwdriver - Gentle...
If it doesn't display on the machine on boot up, then you can't get into it. I think that this is controlled by the little dip switches under the HDD. If dip switches are set as Raid-enabled, you can get into the bios otherwise you...
Clean out the unit (there should be a stick about how to do this). Don't forget the area under the keyboard. Also try ATITOOL to set the GPU/Mem speeds to a lower setting as the factory setting were a bit too high originally.