Many computers take a lot of time to boot (or start ).This is due to
      many reasons.

      Some slight changes can do wonders for your system:

      1.Press start->run then type msconfig and press enter.

      Go to the startup tab. Here you will see a list of startup items. These
      are all the programs that automatically start when you boot your PC. It is
      these that slow down the boot up process.

      So uncheck all the unwanted items like ms-office, messengers other
      utilities that u may not need at startup). Don't uncheck your antivirus
      software.

      Restart your Pc to and see for yourself, your pc will now boot faster....  
           
           
      2.A great new feature in Microsoft Windows XP is the ability to do a boot
      defragment. This places all boot files next to each other on the disk to
      allow for faster booting. By default this option is enabled, but on some
      systems it is not, so below is the information on how to turn it on:

      Go to Start Menu and Click Run
      Type in regedit then click ok
      Find "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Dfrg\BootOpt imizeFunction"
      Select "Enable" from the list on the right
      Right on it and select "Modify"
      Change the value to Y .
      Reboot your Pc and see the change yourself.
        3.SPEED UP BOOT BY DISABLING UNUSED PORTS.!!
      You may have tried many tweaks like modifying windows XP start-up
      applications, prefetches, unload DLLs method, etc. And yes those methods
      do work for me.
      I have just accidentally found out another way to give you an extra boost
      in windows XP's boot performance. This is done by disabling your unused
      devices in
      Device Manager. for example, if you don't have input devices that are
      connected to one of your USB's or COM ports, disabling them will give you
      an extra performance boost in booting. Go to Control Panel -> System ->
      Hardware tab -> device manager Disable devices that you don't use for your
      PC and then restart.