I recently upgraded to windows 2000 from 98 and my computer began running at half the speed. Next I restored 98 using a restore CD and installed 2000 side by side with 98 so I now have 2 operating systems running. In 98 mode, my computer runs at normal speed, 400 mhz. In 2000 mode, it runs at half speed because my front side bus is running at half speed. In 2000 mode, it says my FSB is only 49 mhz while in 98 it reports to be 100 mhz which is the actual speed. Any clues? IBM aptiva 400 mhz, 64 MB RAM, putting in more RAM does not help.