I'm going to try to be concise with this description. I had Windows 7 installed on a 250 GB IDE, and it started having major problems, so finally I just said to heck with it, bought another hard drive and decided to load WinXP on it. I installed the drive, which turned out to be a SATA 500 GB, plugged it in to the SATA 0 port, and loaded XP on it with no problem. After booting to XP for the first time, I noted that my IDE drive was still being recognized without a problem--yay, more storage!
Since I have decided to return to XP and to save Win7 for a later date, I decided to move all my old information from the IDE to the SATA drive, and to reformat the IDE and use it for extra storage. Since it had an OS installed on it, XP wouldn't let me reformat the IDE, so I got brilliant, rebooted with the XP installation disc, deleted the partition on the IDE drive, and then cancelled the XP setup, since I already had XP set up on the SATA drive. (Please note that I am perfectly willing to accept that this may have been a stupid move.)
When I tried to reboot, I couldn't get the computer to recognize the WinXP installation on the SATA drive. It saw the SATA and the IDE without problem in the BIOS setup, but no matter how I reconfigured the boot order or how many times I plugged and unplugged cables, it would not boot from the SATA. So my current fix is this: I went ahead and installed XP on the IDE, and now I am in XP, and I can view and access all my files on the SATA, no problem. Currently the SATA drive is the C: drive and the IDE drive (which is what I'm running XP on) is the K: drive.
Can somebody help me figure out what I did wrong? I want to go back to using the SATA drive for my Windows installation, because I have already set up all my applications and gotten it just perfect. All the files are still there on the SATA; it just won't boot.