If you have lost the original dfrivers, you'll need to find out what chipset your mobo uses.
Try checking during the POST, if its displayed. If not, you may need to open the caase and look on the mobo itself- the chipset numbers are usually printed on there somehwere. If in doubt, just write down everything that looks like VIA 8634 or INTEL i845 or whatever that you see on the mobo and go google
eventually you'll discover your mobo's chipset. Then go download the drivers from either intel.com or
www.viaarena.com for VIA chipsets. Remember you need to know the exact chipset or the drivers wont work, and most chipset drivers are 3-in-1 meaning youll be changing your IDE drivers and sound drivers as well (mileage may vary)
good luck!"