i installed a windows2000 profesional on one hard disk and on another hard disk separately i installed windows xp professional and i used a program called boot-us to give me a menue at the start to switch between the two operation systems and i success but when i select to start with the seconed hard disk with the windows xp it give me the message NTLDR missing and when press any button it start the windows xp a correct mainor what is the reason of the message? thanks

NTLDR is file that you should find in the root directory of the disk or partition where you have WinXP. Maybe the file is damaged. If it is there but you continue receiving that error message, try to move the file to a temporary folder before deleting it. Then insert the Win XP CD-ROM and close any windows that may pop up. Then go to Start/Run, type msconfig and press Enter. You'll see some options at the bottom of the screen, one of which reads "Expand file" (or "Extract file" - I really don't remember now because I'm not using my own computer). Insert the WinXP CD-ROM and close the automatic start-up window that will probably pop up. In the first blank write ntldr and in the second one write d:\i386\win.cab ("d" refers to the letter of your CD-ROM drive, so change it according to your system). In the third blank you write C:\ (or the letter of the hard drive where Win XP is installed). Then click on Expand (or Extract) and you should see a message telling you if the file has been extracted successfully. Try restarting your system now. If everything is OK, you can now delete the copy of the ntldr file that you had moved to a temporary folder. Juan