I was locked out of my windows xp because I could not re-activate windows when I tried I just got a blank blue screen and nothing, eventually I was locked out because the 3 days grace period was over and I ended up buying windows 7, But just before loading windows 7 onto my system I gave it 1 last go and hey presto I did it.
This is what I did rebooted in safe mode then into all user’s and created a new account, after that, I signed out then back with the new account this time when it asked me to re-activate windows the proper reactivation window appeared, and then I just re-activate by phone option (windows re-activation successful).
Hope all is well good luck people.