As a human being, forgetting things are natural and forgetting password is problem of mass population.
Forgot password is very dangerous if you don’t have mechanism to recover the password. Sometime there is a mechanism available to recover the lost password but lots of people don’t know about it. Like in Windows XP there is a mechanism available to recover Administrator password “Windows XP password recovery method” but only a few people of knows about this method.
Previously I have posted an article Recover your Lost Windows XP Administrator Password that describes exact method to recover lost Administrative password and a step by step procedure.