you SHOULD be able to just do a repair installation of XP (instructions bellow) to replace the pirated windows that you have with the legal windows as long as the xp you buy is the EXACT same version as what you installed (i.e. xp pro or xp home, and SP1 or SP2)Repair the Windows XP installation.
To do this, follow these steps:
- Make sure that the CD-ROM or DVD-ROM drive is the first priority startup device.
See your computer documentation for information about how to do this.
- Insert the Windows XP CD into the CD-ROM or DVD-ROM drive, and then restart your computer.
- When the instruction to "Press any key to boot from CD" appears, press a key. Your computer starts from the Windows XP CD.
- When the computer starts from the CD, the system verifies 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 computer 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.
You'll get to keep your existing apps & settings, but you need to re-install SP2, Windows Updates & any unsigned drivers afterwards.NOTE: Be aware that you'll lose any protection from Blaster / Sasser type worms. Don't go online without a firewall, whether the built in Windows one or 3rd party.How to Perform A Re-Install Of XP