I had exact the same problem and the problem is solved.I only update the bios after up[censored] the bios the xp64bit has been istalled easly.Be sure that you update the correckt bios.Now I have Problem at my ethernet it dose not work my board is "K8N" do any boady know how to solve this problem.
For your help the link is
http://www.asus.com.tw/support/download/item.aspx?ModelName=K8N-E%20Deluxe&Type=All