Activate Once Forever
Windows will require re-activation if several pieces of hardware are changed at one time. It makes sense to try to spread these installations out to avoid the hassle.
But what if the WinXP OS must be re-installed on the same system? To avoid having to re-activate, keep a copy of wpa.dbl from the System32 folder with your backups. Make sure to create a fresh copy with any hardware upgrade. Upon re-installing WinXP, just copy wpa.dbl back to the System32 folder to skip activation.