Hi Lois1207,

To use the Sleep feature you have to enable “Hybrid Sleep” in power options as in the picture below (should be enabled by default):

Please follow the below mentioned steps:

1. Click Start button, click Control Panel, click System and Security, and then click Power Options.
2. On the Select a power plan page, click Change plan settings for the plan that you want to change.
3. On the Change settings for the plan page, click Change advanced power settings.
4. On the Advance settings tab, expand Sleep, expand Allow Hybrid Sleep, and choose ON.

Please enable it and click “Apply” and “Ok” to save changes and check.

Check if that helps and reply.

If the above does not work, go into the device manager and click on network adapters to expand it. then double click the adapters name i.e. Realtek family controller. Click the power management tab. Look and see what boxes are checked. If the allow this device to wake computer is checked, uncheck it. Click ok or apply and exit. Restart the computer and then put it sleep mode. See if it stays in sleep mode.

My 630i started doing this after fours years, followed those directions from another post and problem was fixed. Also make sure in power managment you go to the advanced setting. There will be a expansion for sleep. You will see "allow wake timers" if enabled, disable it.