Laptop XP Pro password

Laptop: Compaq nx7400
I have no problems signing on as administrator. If I stop using Laptop for several minutes and then return it asks for the admin password again – I provide this and all is OK. This is a real pain! How can I stop this or at least adjust the time to something more realistic The laptop lives at home with me as a single user and security is not a problem. Ideally I would like to remove the password altogether but I understand this is no possible in XP Pro. Any ideas?