There's a big problem with Sonys. They use bespoke Windows installations, and the drivers that you can download from their web site only work with those bespoke installations. In most cases, you need the Sony recovery CDs in order to reinstall and be assured that everything will still work. You'll often see recovery CDs going on eBay, but because they are so necessary and sometimes rare, they're not cheap. Neither are they cheap to buy from Sony.
I speak from bitter experience. Interestingly, I was able to install Linux on the Sony laptop in question, and everything worked perfectly, including the jog dial!
You may find that you are able to use the repair facility of any Win XP CD, and this for you would be the best solution. Boot up to the recovery console, using such a CD, and then as your first command, run chkdsk /r.
