How to take apart a PC? Please help! 10pts to answerer!?

Q: I have a Dell dimension 2400 desktop PC and I'm trying to install a IEEE 1394 Firewire PCI Card onto the motherboard. Well there are only five screws on this PC that can be taken off from a Phillips screwdriver. There are 4 where the power supply is located and one located on the bottom. The other screws are a circle shape and does not appear that they can be removed. I have no idea how to get inside my PC nor can I find any data that can help me. Anyone who can help me please do so! I will award best answer ASAP! Thanks in advance!

A: http://support.dell.com/support/edocs/systems/dim2400/en/sm_en/rmvcvr.htm no screwdriver required.

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