I recently installed Windows 2003 Server on a second partition of my hard drive. The other operating system installed was the XP Pro that came installed with my Dell Dimension 8400. Since my system was configured with AHCI set on the SATA hard drive, I had to switch it to ATA to install Windows 2003. Now however, I am unable to boot into XP. After picking it from the list of operating systems, it shows the XP boot logo for a second before restarting the computer. I've tried to use the XP recovery cd and used the FIXMBR and FIXBOOT utilities but they haven't had any effect. When I switch the BIOS settings back to AHCI, the same problems occur. Would anyone have any idea on how this could be fixed?