A very important new feature in Microsoft Windows XP is the ability to do a boot defragment. This basically means that all boot files are placed next to each other on the disk drive to allow for faster booting. By default this option is enabled but some upgrade users have reported that it isn't on their setup.
1. Start Regedit.
2. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Dfrg\BootOptimizeFunction
3. Select Enable from the list on the right.
4. Right on it and select Modify.
5. Change the value to Y to enable and N to disable.
6. Reboot your computer.