|Most likely SATA interface hard drives which may require SATA drivers at the start of the installation.|
Why wouldn't you use the Dell recovery disks? Those are free. Any other WinXP CDs have some value, even if you own them.
If you think you can use any CD and it will work you are mistaken. Retail CDs require that you register. Of course only ONE computer can use the same installation key.
Why are you changing the hard drives?
How are they connected? Directly to the motherboard or connected to a controller card?
What is the capacity of the drives?
What is the model number of the Dells?