If you cannot find what you want on the Sony website, here's what I suggest you do. It's what did very recently after installing Win XP on a friend's Compaq laptop.
Use Everest to identify your hardware - graphics, chipset, sound chip, ethernet controller, wireless ethernet, etc. You can tell Everest to save the configuration as a text or html file. Don't overdo it though. Generate only the hardware profile, otherwise you'll end up with a huge file. (My hardware file was more than 300KB in plain text).
Then, you can search for drivers for individual devices. For example, you can look for a suitable graphics driver on Intel's website. The gfx driver is usually the easiest part. Other devices may prove to be more difficult.
If you need further help, post details about the various devices and I'll try to help.
I've just spent a lot of time searching for and downloading drivers for the laptop I mentioned. I downloaded nearly 20 files, out of which I chose the 9 most suitable ones. Windows tried to reject a couple of them and I had to force-feed it. Everything's working fine now. I could even latch on to someone's unsecured wireless internet account (but only long enough to test my installation).