You can download the manual at the following link for your 5536.
You will see the battery in chapter3 page 81.Code:You need to register to see links. Register.
If you can get at it and remove it for around 10 secs or so by just removing the covers (memory cover, hard drive cover etc) then that should clear the password. It is very important that the main big battery is removed also or the password will not clear.
If you cannot get at the battery by just removing the covers, then you will have to follow the dissembly giude in the manual to do so. Ensure you take your time if dissembling and try not to get frustrated as they can be fiddly little things.