Disassembling PS2

[DeVante992]

I downloaded the guide for disassembling a PS2 here .

However, in all the guides I've found, I haven't found one that says how to remove the bottom metal guard on the bottom of the motherboard.

I have the entire motherboard away from the case and DVD-drive.

However, I can't seem to peel the metal guard away from the motherboard. It just won't give.

I've removed the upper metal guard with no problem.

Can anyone tell me what's keeping the bottom metal guard there, and how I can remove it?