Please follow the steps below- 1. Check how much RAM your pc use by going to the properties window. 2. Press the “Win+R” button to start the run command. 3. Write “msconfig” and press enter button. 4. Go to the “Boot” tab of the newly opened system configuration window. 5. Press “Advanced Option” from below. 6. Untick the “Maximum Memory” option. 7. Restart your PC to take effect with the whole RAM.