If you make all these changes you will have to do a repair installation and
probably reactivate. However it is not a problem. To do a repair
installation:
Start the operating system from the CD-ROM,
When the computer starts from the CD, the system checks your hardware
and then prompts you to select one of the following options:
To set up Windows XP now, press ENTER.
To repair a Windows XP installation using Recovery Console, press R.
To quit Setup without installing Windows XP, press F3.
Press ENTER.
Press F8 to accept the Licensing Agreement.
A box lists your current Windows XP installation, and then the system
prompts you to select one of the following options:
To repair the selected Windows XP installation, press R.
To continue installing a fresh copy of Windows XP without repairing, press
ESC.
Press R to start the automatic repair process. After repairing Windows XP,
you will need re-download all updates, starting with SP1.