Did you install on WinXP every specific driver from the MB manafacturer???

Most of the windows just uses general drivers which in some cases can show unusual behaviours in terms of performance and strange crashes.

Try to check the motherboard site for updated drivers for your chipset.

Hi everyone.

Above the bug reported above, I had a similar problem and in the end the problem was hard drive the got some bad sectors, and although they were marked not to be used the all performance itself decreased.

Try to run a scandisk to check the heath of your disk