By default in Windows 7 when your Computer is idle for certain time the Computer goes into Sleep mode, after user moves Mouse or presses any key on keyboard Windows prompts user to enter he passowrd which can be irritating and annnoying certian times which we can disable this feature in Win7 very easily.
To stop Win7 from asking for password after computer wakes from Sleep
Click Start button>Control Panel>Hardware and Sound>Power Options
Click Require a password when the Computer wakes, select Don’t require password and save changes.