You simply install windows XP. Then you repair Windows 7.
BTW, in order to install Windows XP/7, you need to boot from the CD, instead of booting from the hard drive. So, you need to go into BIOS and change the boot up priority. After you are done with XP, insert windows 7 CD, and choose repair installation. then change back the boot up order to the hard drive and you are done
the dual boot menu is created automatically, you dont have to do anything. Having said that, you may afterwards download an application for windows called EasyBCD, its free and allows you to change dual-boot settings.
First, have you tried installing the programs using XP compatability mode. Can select this by RIGHT clicking the installation app then select compatability mode. This will probably work with 95% of all programs that run under WinXP, (64 bit win 7 - exception of WinXP programs that has 16 bit code)
If you still want/need XP then leandrodafontoura method is not my choice.
My Choice (requires 2 HDD).
Disconnect win 7 HDD
Connect (or leave connected) 2nd HDD. If reusing a 2nd HDD BACK up all YOUR data!!
Install win XP on 2nd HDD
When completed with win XP install on 2nd HDD, reconnect Win 7
NO SOFTWARE Boot manager to mess you up.
With Bios set to first boot Win 7.
during post hit the function key that brings up the boot order and select HDD with XP on it.
.... On my Gigabyte MB it's F12 and on my Asrock MB it's F11.
... This does NOT change Boot priority in Bios.
... The drive you boot to, that operating system will be "C-drive" ie boot to win7 and win 7 will be "C". Boot to XP and XP will be C drive.
... You can still access the 2nd HDD for read/writes. Ie Boot win 7 and you can still see and use HDD with win XP (Just can not run win XP programs - to do that you must boot to XP. The opposite is true if you boot to XP