It does sell with XP >>>
Products & Services - Notebooks
Aspire 5720 (Vista only listed - See below) >>>
http://support.acer-euro.com/drivers...k/as_5720.html
TravelMate 5720 XP and Vista Listed >>
http://support.acer-euro.com/drivers...k/tm_5720.html
FTP directory so you can get all if have the aspire 5720, there is XP drivers for it here I am sure. But Since I do not know the exact specs of your laptop I cannot post direct links.
So I will look for the driver page and post back/edit this in one sec