|Rightclick My Computer & select Properties|
Under the Advanced tab click on Startup & Recovery settings.
Set XP as the default operating system and set time-out to zero.
save & exit.
This is the easy way for dummies.
You can manually edit the Boot.ini file to remove all reference to the other operating system but there is a risk you may mess it up & be unable to boot into XP.
Goin' Fishin' (Some day)