Earlier today me and my brother took apart my computer to clean out the case then we put everything back in the same way it came out. The problem here is that when i boot up the bios says "Secondary master not located." so then we unhooked the main Cd-rom and it didnt find an error then we hooked them both back up and the error again.I did not mess with any of the jumpers for the cd-roms so that shouldent be a problem.. If you need anything else just ask.. Thanks in advance