Vista - instaling xp over vista on hp dv2910tx

I have tried loads of internet sites for this. I have got a partition for XP and one for Vista. I booted the laptop from the XP cd. Now it cant find my hard drive. I tried to disable my SATA driver but that option isnt available on my laptop. The customer care says i can make a floppy drive of the driver and insert when prompted in the setup. But i dont have a floppy drive. And they say, i cant do anything else. I, however, got the driver and tried to incorporate in the xp setup using nlite. But then my laptop doesnt boot from that custom cd. I am stuck. I do however want my vista as well on the laptop. I dont want to clean it. I also am not able to find all the other drivers. I got hold of the ones on hp support site. But still some of them are missing. Please help!