Boot up in Safe Mode, and log in under the Admin account.
Click START->RUN->then type control userpasswords2
Click the ADVANCED tab, then under ADVANCED USER MANAGEMENT, click ADVANCED.
Click on the USERS folder. in the right hand pane, now right click on your profile, then click PROPERTIES.
Place a check in the box, PASSWORD NEVER EXPIRES. click APPLY, then OK. reboot and attempt to login to XP in normal mode.
after how long does it expire?
unfortunately i've got xp home