1. Insert your Windows XP Pro CD into the CD drive and reboot your computer.
2. Press the letter 'R' on your keyboard when the 'Welcome' screen appears. Be patient, getting to the welcome screen takes some time. This will bring up the Windows Recovery Console.

3. Enter your administrator password. If you don't know what this is, just hit 'Enter.'
4. Select option '1.' This screen is showing you the various Windows installations on your computer. This is only a concern if you have a multi-boot system, most of the time that will not be the case. If you see more than one selection, and you are not sure which number to choose, go ahead and select '1.'
5. Wait for a few minutes, this process takes some time. When the recovery console has loaded, your screen will have a command prompt or look something like 'C:\'
6. Type the following commands, without the quote marks. 'Copy D:\I386\NTLDR C:\' hit'Enter.' Next, type 'Copy D:\I386\NTDETECT.COM C:\' hit 'Enter.' In these two commands, the 'D' represents the CD drive that holds your Windows disk. This assumes that drive is letter D. You will need to change this letter if your CD drive is labeled with a different letter.
7. Remove the Windows CD and restart your computer.