Sleep Mode is an energy-conserving function of computers that shuts down most of their systems, including the monitor and the fan, and keeps a small section of memory running to store the programs that were running at the time sleep initiated. It activates automatically after a set amount of inactivity. While Sleep Mode is useful for extending the life of the computer and saving power, it can have glitches that vary depending on the make and model of the specific computer. If you have an HP computer that won't come out of Sleep Mode, you can find ways to fix it.
Press the "Sleep" button on the keyboard. On HP computers, it will be near the top of the keyboard and it will have the symbol of a quarter moon on it. Move the mouse as well to see if either will wake the computer up.
Hold down the power button for five seconds. This will frequently jar a computer out of Sleep Mode or it may cause a total reset, which will also restart the computer normally again.
Check your power supply. If the computer is running on a near-dead battery, it may not be able to come out of Sleep Mode. Check that you have the computer properly plugged into a working outlet, if it is not running on a battery.
Access the Control Panel via the Start Menu and select "Hardware and Sound." Click on "Keyboard." From there, click on "Hardware," "Properties" and "Change Settings." Check the box next to "Allow this device to wake the computer" under "Power Settings." This will enable the keyboard to wake the computer up from Sleep Mode in the future.
Access the Control Panel via the Start Menu and select "Appearance and Personalization." Choose "Screensaver" and change the screensaver or turn it off. Some screensavers interfere with the computer's ability to enter or come out of Sleep Mode.
Download any available patches to your operating system. The trouble may be the operating system rather than an issue with your HP computer. Updating the operating system can prevent the issue from reoccurring.