I have just removed my lan card from it's PCIx1 slot to make room for a double slot graphics card. The only spare PCI slot I have is bigger than x1, can I just plug the lan card straight into it and have it work? Does it matter which end it goes in? (the spare slot is the white one on the pic of the motherboard)
That white slot is a PCI slot, not a PCI express slot. So you can NOT install your PCI express card in anything but a PCI express slot! And yes, you can install a smaller PCI express card in a larger PCI express slot if need be, no problem (of course, you don't have that option anyway).