This list shows how the WPA program works and could save you headaches later.   The goal is keep 7 YES votes. Change too many hunks of hardware or the wrong parts at once, you you might be calling Microsoft to activate windows.
 
With 7 YES votes, you should not be prompted to reactivate Windows XP.

WPA checks ten categories of hardware:
1. - Video card.   (gets one vote)
2. - SCSI adapter (gets one vote)
3. - The IDE adapter (the motherboard's IDE hard drive controller)   (gets one vote)
4. - Network adapter (NIC) and its MAC Address     (gets 3 votes)
5. - RAM - amount and range (i.e., 128 to 256MB, 256 to 512MB, etc.)   (gets one vote)
6. - The processor's type - the make and model of processor(s) (gets one vote)
7. - The processor's serial number   (gets one vote)
8. - The hard drive   (gets one vote)
9. - The hard drive's Volume Serial Number (VSN)    (gets one vote)
10. - The make and model(s) of CD/DVD drive(s) installed.   (gets one vote)