XP activation

[sentme_mail]

hi,
i recieved this popup on my XP home edition startup.
It says :
" This copy of windows must be activated with Microsoft before you can log on.
Do you want to activate Windows now?"
i tried clicking "yes" and "No" it does not allow me to logon.
the PC is a standalone.
any help?
thanks

 

[JohnWill]

Call Microsoft, they have an 800 number for activation issues.