Final answer:
If your desktop won't turn on after upgrading the RAM and the monitor is also not working, possible causes could include incompatible RAM, PSU issues, or installation errors. To troubleshoot, check compatibility, reinstall old RAM, test the PSU, and verify all connections are secure.
Step-by-step explanation:
If your desktop won't turn on after upgrading your RAM and your monitor also won't turn on, there could be several possible causes for this issue. One possibility is that the new RAM you installed is not compatible with your computer's motherboard. Another possibility is that there is an issue with the power supply unit (PSU) in your desktop. Additionally, it's possible that there was a mistake made during the installation process, such as not properly connecting cables or seating the RAM correctly.
To troubleshoot this issue, begin by checking the compatibility of the new RAM with your computer's motherboard. Look for any specifications or requirements that need to be met for the RAM to work with your system. You can also try removing the new RAM and reinstalling your old RAM to see if that resolves the problem.
If the RAM is compatible and properly installed, then you may want to check the PSU to ensure it is functioning correctly. You can try testing the PSU by using a multimeter to measure the voltage outputs. If the PSU is faulty, it may need to be replaced.
Lastly, double-check all connections, including power cables, monitor cables, and RAM seating. Make sure everything is connected securely. Sometimes, a loose or improperly connected component can prevent the computer from turning on.