If you're willing to spend several hundred dollars just for
a Linux test bed, consider getting a refurbished
not-too-recent desktop system from Tiger Direct or one of
the refurb houses. A new machine, and especially a new
price-pointed laptop, may give you configuration grief that
a more pedestrian box might avoid.

When you do start the installation, ensure that you have a
fully functional web-and-email system up and running
alonside your new Linux pc - you want to be able to google
for info at every step of the way, rather than try&die, just
like any other adventure puzzle. Once you've built it up
and stripped it down a couple of times you'll bettter
prepared to repartition and dual-boot one of your XP boxen.