Additional information required! What motherboard do you have? You can open the case and check or use CPU-Z to find MB model number. If your computer is OEM built (depending on who built it) you may have to contact the manufacture to find out supported CPU’s . Truthfully I would not invest any money into that computer. Save for a new one. If your board is a socket 423 the processor prices are higher and there is a smaller selection of speed bins than socket 478.