I just changed my PSU and upgraded my graphics card today. I tried booting it up and it came up with this message "reboot and select proper boot device or insert boot media in selected boot device and press a key."
I'm pretty sure I got all the cables in correctly and I only have one harddrive. No externals. I honestly have no idea what is going on and would appreciate it if someone could help me. By the way, I don't have my windows 7 CD because I let a friend borrow it and I won't be able to get it back for some time. However, I do have a Windows XP CD if that helps in any way.