I forgot to ask. What is that PCI Express slot used for so?
It is used for graphics cards but only 1x card types which i doubt very much you have the connectors on the card will be the same size as the slot. Didn't want you to think you could use it .
You would normally have other PCI express slots if you have this slot type. You could get a 1xPCI E card, i know matrox do them, but there very basic cards you've got a much better variety of pci cards. It might bo worth using if your pci sockets are 32 bit 33mHz but if there 32 bit & 66mHz or 64 bit & 66mHz they are faster than PCIEx1.
PCIE 1x & 8x can be used for devices other than graphics, but 16x is only used by graphics at the moment.