This command will force the OS to process all idle tasks. If your PC is never idle these tasks will never run. One of the tasks that Windows XP performs during idle times is the optimization of the files needed to start the OS. These files will be re-arranged on the disk and match the exact order they are loaded during startup. This list is in C:\Windows\Prefetch\Layout.ini.

To get more XP Speed Performance with the eye candy, follow the next steps:

1. Click Start -> Run
    
2. Type: rundll32.exe advapi32.dll,ProcessIdleTasks.

Note: After step 3 idle tasks will operate in the background. Heavy disk access is likely. This process could continue for a few minutes.