From here;
http://www.geek.com/forums/topic/cpu-100-usage-problem
"NTLDR is a program loaded from the hard drive boot sector in Windows NT, Windows 2000, or Windows XP, that displays the Microsoft Windows NT startup Menu and helps Microsoft windows load.
You can find a good, succinct report on the NTLDR error at
www.microsoft.com/Default.aspx?kbd=314057
The cause is one of the followin:
A. The computer attempting to boot from a non-bootable source.
B. The hard drive isn't correctly setup in the BIOS.
C. Loose or bad IDE/EIDE cable.
D. Virus or Malware damage or corruption.
E. Damaged Windows version of NT, W2K, or WXP.
F. Damaged or corrupt NTLDR and/or NTDetect.Com files.
G. Damaged or corrupt boot sector or the master boot record.
H. Improper configuration of the boot.ini file.
I. Upgrade attempt to NTFS file system from Windows 98, Windows ME on a computer that has FAT32 file system.
J. Adding a new hard disk that is not properly configured or setup.
K. Attempting to boot from a non-bootable floppy disk or CD-ROM (or that a floppy disk is mistakenly left in the floppy drive.)
L. Floppy disk from which you are attempting to boot is missing some key files.
M. CD-ROM boot is damaged, scratched, or missing some key files and folders.
N. Damaged or defective CD-ROM drive.
O. Jumpers on CD-ROM or hard drive are not properly set.
P. Memory stick is in the card reader, and the setup is attempting to boot from the memory stick.
Q. Hard Drive is not correctly setup in the BIOS or CMOS.
Once you are sure your BIOS is properly setup, FDISK and reformat your hard drive, then boot from a valid install disk. As the computer is booting, you should get the common Windows message asking or telling you to
Press Any Key to Boot from the CD. Otherwise, the computer may attempt to boot from the hard drive. A better way to do this is to go to the BIOS, and reset the boot order so the CD-ROM is in first position, or second position behind floppy disk drive.
This is usually all you need to know to get it right. Use a newly formatted drive. Then boot to a valid CD and let it restructure the hard drive as NTFS.
In addition to the microsoft knowledgebase article posted above, you can find a great deal of useful information on what to do by doing a Google search."
