While there's no specific sleep button, you can just click the little arrow next to the shutdown button to get additional options:
If the shutdown button is missing from the log on screen, open
regedit.exe, and navigate to
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System. Then make sure the
ShutdownWithoutLogon value is set to
For Professional, Ultimate or Enterprise editions only:
- Click on Start, type
gpedit.msc in the search box and press Enter.
- In Local Group Policy Editor navigate to User Configuration > Administrative Templates > Start Menu and Taskbar.
- Double-click on Remove and prevent access to the Shut Down, Restart, Sleep, and Hibernate commands.
- Make sure the setting is either set to Not configured or Disabled.
- Apply the changes and press OK.
This policy setting prevents users from performing the following commands from the Start menu or Windows Security screen: Shut Down, Restart, Sleep, and Hibernate. This policy setting does not prevent users from running Windows-based programs that perform these functions.
If you enable this policy setting, the Power button and the Shut Down, Restart, Sleep, and Hibernate commands are removed from the Start menu. The Power button is also removed from the Windows Security screen, which appears when you press CTRL+ALT+DELETE.
If you disable or do not configure this policy setting, the Power button and the Shut Down, Restart, Sleep, and Hibernate commands are available on the Start menu. The Power button on the Windows Security screen is also available.
Source: Group Policy Search