Just in case anyone has this problem, I'm posting my solution. I found I was unable to do a re-install of XP because the BIOS wouldn't boot from the CDRom with XP installed on the HDD. I had a Master HDD fail on an old system - so old that the original OS disc was SP1! I installed a new Master HDD, but ran into issues after a while because I screwed up the installation procedure, and ended up with the slave as C drive and the Master as E. Thought OK, I'll reinstall, and this time disconnect the Slave for the reinstall, after renaming it as F. So I set the BIOS to boot from CDRom, and it just wouldn't. All settings were to CDRom, but it wouldn't - it insisted on booting from the E drive where the OS was installed. It wouldn't do an XP Repair, running off the XP original disc because the disc is SP1, and won't repair the online-upgraded SP3. I tried copying the Repair module from another system's XP-SP3 disc to the HD and running Repair from that, in the hope that it would start changing enough files to include the crucial one that I assumed was overriding the BIOS settings. That didn't work either. I tried getting into the Command Prompt and just running format C: but XP won't allow that. The answer was to run an old CDRom of Partition Magic, at least 6 years old. I tried first to format the OS drive but it didn't like that, so, with nothing to lose, I selected the OS partition and just hit Delete. Stuck the original XP-SP1 disc in the drive ensured the BIOS was set to boot from there, and this time the BIOS recognised the CD drive, and the re-install procedure started.
Weird, never had boot from CD problem before. You sure it didn't have Press any key to boot from CD... (for like 3 seconds) ?
Hmm.. The BIOS should have an option to change the boot sequence. E.g. HDD0 -> CD-ROM. Perhaps that was not set correctly? If it was set correctly, it will give you the option to boot from the CD (for a few seconds) before it defaults to a hard disk drive. If you do not watch the boot screen, you may miss the message and the computer will proceed to boot up the hard disk drive. In such a case, I would just remove the OS drive (if it's a separate hard disk drive) and install Windows on the replacement HDD before putting the second drive back in.
Thanks Adrian and Zy. I looked out for that short prompt to press any key to boot from CD-Rom but never saw it. The BIOS did have that option to change boot sequence. First I put CD-Rom first, and when that failed to find the XP install disc I set all three to CD-Rom. And still it booted from HDD.
Hmm.. That's odd. It shouldn't work like that. Even if you have bootable hard disk drives in the PC, the BIOS should allow you to force the PC to boot from the CD-ROM.
