Dumb question-
Does your bios detect the hard drive?
If yes, then the problem is purely with the fault of xp's inability to talk to the controller properly.
In the old days, this would mean, grabbing the appropiate ahci drivers off of the appropiate website, making a floppy disk, and stabbing f6 for all it was worth as the xp setup engine started. (Ye olde: Press F6 to install Third Party Driver) and hoping that nothing was wrong with either the floppy or the text file, and it would read correctly and that it was coded properly.
Of course, there's been the death of the Floppy, and getting 1.44mb disks is nigh impossible. (Hooray!)
Which leaves the only other way to integrate a driver into the windows xp disk, is to use 3rd party tools like
nLite to integrate the files onto a burnable CD.
http://www.computerhope.com/help/phoenix.htm#03
If the laptop bios is anything at all similar to what is linked above, you should be able to change the controller type.
Other dumb question because right now all you will be getting is generic answers since you haven't mentioned manufacturer or model number of your laptop.
(Bottom of the laptop, there should be a label beside the windows sticker listing manufacturer and P/O number.)
Knowing who the manufacturer is and what specific laptop it is will allow this generous host of nerds the ability to obtain drivers and write detailed specific instructions on what you are dealing with.
Otherwise, you could get a vista cd and install that, but vista sucks so I suggest geting windows 7 instead (apparently it's been flying off the shelves the hype has been so high) and dealing with the new opportunities to deal with newer (Undocumented Features)