To remove the need for password after hibernation:
-Control Panel->System and Maintenance->Power Options.
-Click on Change plan settings for your selected plan.
-Click on Change advanced power settings.
-Click on Change settings that are not currently available. Give permission to continue when User Account Control dialog pops up.
-Find Additional settings. Expand it, then expand Request a password on wakeup
-Change it to No, if it's for a laptop you have to do it for Battery and Plugged in.
-Click Apply and then Ok.
Anyways to reset a lost password you'll need to enable the so called "super" admin account which is disabled/hidden by default on Vista or use a third party application. Why do you not want to reset a password legally? lol.