You can update windows 2000 with windows 2003. Enter the cd which can boot your pc and which label is window 2003, and boot from it then follow the instruction by given your pc. after some. the 2003 will automatically check for installed os and it will ditects the window 2000. now your computer will give you two options once for udate and another for install newly. now choose update and then star updating. BYe..