In Control Panel>User Accounts>Remove Password. You may need to enter the Admin password to achieve this.
Then be sure there is no Screen Saver (not needed since CRT monitors) set in Control Panel>Personalize.
If this is the original factory preinstall I would consider doing the superior Clean Reinstall - Factory OEM Windows 7
to get the best possible performance from Windows 7 and set it up exactly the way you want.