If your computer doesn't automatically start from the CD or you cannot press a key to boot from CD, you may need to enter the BIOS and change the boot order. To enter the BIOS, press your PC manufacturer's BIOS key, which is usually F2, F10 or F12 as the computer boots. Sometimes this key is displayed on the first boot screen. Then look for the boot order section, set CD as first with hard drive as second, then save and exit the bios and reboot.
Get hold of a Windows XP disk and then do the following:
1. Insert the Windows XP bootable CD into the computer.
2. When prompted to press any key to boot from the CD, press any key.
3. Once in the Windows XP setup menu press the "R" key to repair Windows.
4. Log into your Windows installation by pressing the "1" key and pressing enter.
5. You will then be prompted for your administrator password, enter that password.
6. Copy the below two files to the root directory of the primary hard disk. In the below example we are copying these files from the CD-ROM drive letter "E". This letter may be different on your computer.
copy e:\i386\ntldr c:\
copy e:\i386\ntdetect.com c:\
7. Once both of these files have been successfully copied, remove the CD from the computer and reboot.
I know it is an old post, just in case he/she is still looking for a cure. :)