I installed windows 8 on a new partition on my really old computer. Something I did made windows 8 not boot anymore (I don't want it on my computer, I want to fully revert back to XP). But, XP won't boot either! The error message when trying to boot xp is: Windows failed to start. A recent hardware or software change might be the cause. To fix the problem: ... <instructions to repair computer using dvd>... File: \ntldr Status: 0xc000000e Info: The application or operating system couldn't be loaded because a required file is missing or contains errors. When I google it, all I find are instructions that assume your windows vista (or windows 7 or windows 8) partition still boots. I need instructions that work from the xp cd's repair command prompt. I already tried going into the xp recovery console and running fixmbr plus I copied ntldr and NTDETECT.COM from the cd to the C:\ drive. I still get the same error message.