I got sick of XP home after about the first 10 minutes on my new GR390 a couple of months ago. I also called Sony and found out that W2K restore disks were not available. I then tried upgrading to W2K Pro using an off-the-shelf W2K Pro "upgrade" edition, thinking that may have been the idea, that home was more "upgradeable" than prior OSes. Sure enough, worked like a champ. All the existing drivers worked just fine, as have all the Sony and Microsoft updates since.
WXP Pro has turned out to be very solid, as good as W2K Pro so far. I use W2K Pro on all my workstations.
With a bit of effort you can make XP Pro look and work like W2K🙂
* Turn off system restore. This one nails disk and processor power.
* Turn on "windows classic" theme to get rid of the Fisher-Price look and feel
* Turn off all the animations. There are a dozen of them on a list.
* Right click on the task bar and go to properties. Turn on "my computer", "my network places", etc. on the start menu.
* Go to windows update and install all the bug fixes.
Good luck!