Read the part of my guide about slipstreaming Sata drivers using nLite.
It's all on my site and you should be able to make a new XP cd.
HP DV6500T Triple Play XP
Scroll down a little bit where in says Removing Vista and Installing XP.
Read the part about nLite. The sata drivers on my site will probably work if you have an Intel processor. Otherwise there's a link for the AMD processor laptops.
The other option is to turn off Sata in the bios until you get XP installed, but that's only if your bios allows Sata to be turned off. The new HPs don't allow it, which is why you use nLite to slipstream the drivers.