You'll need to clone the IDE to SATA, Acronis True Image has a free 15 day fully functional trial, wait to download and install until you're close to doing the clone.
http://www.acronis.com/homecomputing/download/trueimage/
Install Acronis on the original source HDD to be Cloned, requires a Reboot to complete the installation, then shutdown the computer and connect the New SATA HDD, boot into Windows and open Acronis, bottom left of Pick A Task Window, Select: Manage Hard Disks Select: Clone Disk
Choose the Automatic Cloning Feature, if the SATA drive is new and blank the cloning will start automatically, when the cloning completes your computer will shut down, then remove the Source IDE HDD before rebooting the computer, upon reboot Acronis will complete the cloning process and you're done.
Then you'll need to do a Repair reinstall of WinXP, [Looses Zero DATA] to recognize all the new hardware, and you'll be in business.
To do a Repair Reinstall of WinXP, Insert and boot into the WinXP Installation CD and begin the installation like you are installing from scratch, Press Enter when it requests a response from you until you get to the F8 Agreement Screen, after you press F8 to agree, the next screen scans for old installations and will find her old WinXP installation and highlight it, Press R, and the Repair begins, you'll have to re-Enter the product key, and when the Repair Install completes all her old DATA will still be there.
I suggest doing the Cloning first on the old machine, then the Repair Reinstall on the new, it would be better if the cloning could be done on the original computer, If it has SATA capabilities.
EDIT NOTE; Acronis automatic cloning mode will also convert the older say, [Example] 20G HDD to the new say 500G HDD, expanding the original 20G partition to the full 500G size of the new HDD.
I would not recommend anything to you, and especially give you instructions on how to use it, if I was not 100% confident it would work for you, I have done this procedure many, many, times. Ryan