If your Dell G15 5515 laptop is unresponsive and not responding to your input, here are some troubleshooting steps you can try:

1. Force Restart: If the laptop is completely unresponsive, press and hold the power button for about 10-15 seconds to force a shutdown. After that, press the power button again to turn it back on.

2. Check Power Supply: Make sure that the laptop is connected to a power source and that the battery is not critically low. A drained battery can sometimes cause unresponsiveness.

3. Disconnect External Devices: If you have any external devices (such as USB devices, printers, etc.) connected to the laptop, disconnect them and see if the issue is resolved.

4. Remove and Reinsert Battery (if applicable): If your laptop has a removable battery, try removing it, wait for a few seconds, and then reinsert it. This can sometimes reset certain hardware components.

5. Run Hardware Diagnostics: Dell laptops often have built-in hardware diagnostics. Access these diagnostics by pressing the appropriate key (usually F12) during startup and selecting "Diagnostics" from the boot menu. Run a comprehensive diagnostic test to check for any hardware problems.

6. Check for Overheating: Overheating can cause the laptop to become unresponsive. Check the laptop's cooling system and make sure the vents are clean and unobstructed.

7. Boot into Safe Mode: Try booting the laptop into Safe Mode. This will load a minimal set of drivers and services, and if the laptop works fine in Safe Mode, it might indicate a problem with a specific driver or software.

8. Update Drivers and BIOS: Ensure that you have the latest drivers and BIOS updates installed from the Dell support website. Outdated or corrupted drivers can cause various issues.

9. Reset Operating System: If the laptop remains unresponsive, you can try resetting the operating system to its factory defaults. This will reinstall the OS and remove any software-related issues.

10. Contact Dell Support: If none of the above steps resolves the issue, it's best to reach out to Dell Support or take the laptop to an authorized Dell service center for further diagnosis and repair. They can provide specialized support and help you resolve the specific issue with your Dell G15 5515 laptop.

Note: Performing a reset or reinstalling the operating system will erase all data on the laptop, so make sure to back up any important files before proceeding with these steps.