According to Intel, no you can't. All other sources I looked at says the same. The C2D's are LGA775 as well(the chipset on that board), so if you have one then all I can say is "try it." I don't really see why it wouldn't work, except voltage needs. I'm pretty sure I had the same motherboard with a E8400 in it. Unfortunately, I can't say that for definite as a few 945 boards were made and I can't recall the exact one I had. If it was free and you don't care about it much, take a stab at putting one in there and see what happens! It'll probably work and boot up and all that, but it'll probably be highly unstable if that processor isn't getting enough juice.