Try this bootdisk (also works with windows NT/2000)
No need to format your hard disk. Just load the disk and change the password. So insecure :)
http://home.eunet.no/~pnordahl/ntpasswd/
* Not applicable to windows with FAT32 file system
For FAT32 FS, just delete the SAM file an SAM.LOG in
c:\windows\system32\config and replace with default SAM file available in c:\windows\repair
download microsoft boot disk (from all range of Windows OS) here
http://freepctech.com/pc/002/files010.shtml
some complete with useful command DOS file such as
attrib.exe, deltree.exe, doskey.exe, edit.com, emm386.exe, extract.exe, fdisk.exe, format.com, himem.sys, mem.exe, more.com, mouse.com, move.exe, mscdex.exe, reboot.com, scandisk.exe, scanreg.exe, smartdrv.exe, sys.com and xcopy.exe as well as a generic IDE CDROM driver.