Re: dual booting vista and xp.
No. That is how i got my system Dual Booted.
Install XP. Use EasyBCD. Reinstall the boot loader. From within XP get all the details of your boot. Under the msconfig>Boot.ini tab.
Go into the EasyBCD setup and edit your boot loader. Add the XP details and you should be all set.
I make it sound easy cause it is. The only issue i had was both XP and Vista thought they were the C:\ drive which confused the EasyBCD application. Which i was still able to get around.
I do not accept support questions via EMail, PM, IM or my G+ page!
Phone: LG Optimus G Pro
Running: Stock JB from LG with Nova Launcher