How to Fix System is dead, no cursor, no beeps, and none of the fans working
When computer is no longer powering on there are few possible causes you will need to check to find out what is causing the computer not powering on. I will list troubleshooting steps you should follow to resolve a computer not powering on.

1. Power cord failure. Power cords can fail even though they look fine. Testing Power Cord Continuity. Plug in or replace the power cord.

2. Power supply failure. Replace the power supply. Use a known, good spare for testing. Test the Power Supply Using using Voltmeter. Testing the DC voltage output of the power supply using a digital multimeter can help you isolate any potential issues and determine if you have a bad power supply unite.

3. Motherboard failure. Replace motherboard. Use a known, good spare for testing.

4. Memory failure. Remove all memory except one bank and retest. If the system still won’t boot, replace bank 1and retest.

5. All components either not installed or incorrectly installed. Check all peripherals, especially memory and graphics adapter. Reseat all boards and socketed components, such as CPUs and memory modules.