When I shutdown My pc it working on sleep mod

It sounds like your Dell Vostro 2520 is not fully shutting down when you select "Shutdown," and instead, it's going into a sleep mode. You can try the following steps to troubleshoot and fix this issue:

1. Update Windows: Ensure that your operating system is up to date by installing the latest Windows updates.

2. Check Power Settings: Go to "Control Panel" > "Power Options" and make sure that the power plan is set to "Balanced" or "High Performance." Adjust the settings to prevent your PC from going to sleep when you shut it down.

3. BIOS Settings: Check your BIOS settings for any options related to power management. Ensure that the settings are not causing this issue.

4. Fast Startup: Disable "Fast Startup" in your power options. It can sometimes cause problems with full shutdowns.

5. Update Drivers: Make sure all your device drivers are up to date, especially the graphics driver.

6. Run Troubleshooters: In Windows 10/11, you can use the built-in troubleshooters. Search for "Troubleshoot" in the Start menu, and select "Power" troubleshooter.

7. Hardware Check: If the issue persists, there could be a hardware-related problem. Consider having your hardware checked by a professional.

If the issue still persists after trying these steps, it may be a more complex problem that requires further investigation by a technician.

In the power settings there is the option to define what happens when you press the power button.

open the control panel, go to power options.

In the left panel open Choose what the power buttons do

select the function you want when you press the power button.