[Halcyon]

Before you do anything, backup all your important files you want to keep.

Next thing to do is to go to the Sony website and look up your laptop model number.

Hopefully they should have provided drivers for XP too. Download all the drivers for XP or else otherwise you'l install Windows and the hardware won't function at it's best.

Install Windows XP, Install the laptops XP drivers you got off the website....for ethernet, graphics, etc.

Re-install your data files.
Done.