I have an old Dell Dimension 2400 and not enough money to get a new comp but the game I play need PCI express cards to play them is there a way to make one of mt PCI slots an express slot or is there an adapter or something I can buy???
Nope. You should be able to find some old PCI cards that are capable of at least starting most games [ATI 3850 comes to mind...], but for all practical purposes, they will be too slow to offer and real playable performance.