How do i change my password on my computer?

take START>CONTROLL PANEL>USER ACCOUNT> as well as take your current label should you have far more company accounts as well as clients within your PC in addition to proceed CHANGE PASWORD

http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/windows_password_change.mspxmfr=true

http://support.apple.com/kb/ht1274.