Hello and welcome. First we need to know if it’s a BIOS password, meaning it won’t even start the windows login screen, or if it’s the Windows login password that you don’t have. If it’s the BIOS password your options are limited, but if it’s the login password you might be able to boot into safemode when the computer starts up and from there you might be able to login as ‘guest’ and reset the password. Next, you don’t have to boot the Windows XP install disk to install Windows. As long as you have a working CD rom drive, you mentioned a USB drive, you can run the setup program from the XP disk without booting it. Post back about which password you do not have.