You have an old 915 chipset in BTX format, which is hard to find. You can find them used on ebay. Computer geeks carries a fujitsu siemens 775 btx board for only $6.99, but it has no cpu fan connector or backplate, which your dell may not need. It won't load your original windows operating system unless you've already upgraded that to oem or retail boxed. The original windows requires another dell motherboard. If you want more choices, change to an atx case, or start over and sell your old dell intact or use it for a spare. BTX motherboards have older chipsets; a few were made with the 965 chipset which will work with older core2 duos, such as the e6400. Compare the dell to the fujitsu siemens; it's much cheaper. Used dell e310 boards go for around $100 at some stores. I haven't checked ebay for pricing.