Problems that occur as a result of installing Windows XP (and subsequently installing all Windows Updates) on a system that had been working usually are caused by NO DRIVERS or WRONG DRIVERS being installed. Microsoft does not think that searching for proper drivers for your computer's hardware is a Windows XP problem. That is why computer hardware manufacturers (the good ones) post drivers on their website and/or give you a driver CD.

If there is a driver CD that came with the computer, use it to install the proper drivers over the drivers that Windows ''thinks'' should be used.

If no driver CD, then go to Sony.com and download and install the drivers for your particular model. Use the newest driver listed. Follow the installation instructions for the particular driver.
http://esupport.sony.com/perl/select-system.pl?DIRECTOR=DRIVER

Don't use the drivers that Windows Update suggests for your machine, and don't let Windos automatically choose a driver when clicking the Update Driver button in the properties of a device.