It sounds like you have already tried some basic troubleshooting steps, such as changing cables and attempting to reset the PS3. Here are some additional suggestions you could try to get your PlayStation 3 working again:
***Check the power supply***: Make sure the PS3 is properly plugged into a power outlet and that the power cable is in good condition. You could also try plugging the PS3 into a different outlet to see if that makes a difference.
***Test with another TV***: If possible, try connecting your PS3 to another TV to see if the issue is with your TV rather than the PS3.
***Try a different display setting***: Sometimes the display setting on your PS3 can get changed accidentally, causing the screen to go blank. Try changing the display setting to a different option, such as 720p or 1080p, and see if that fixes the problem.
***Remove any discs or USB devices***: If there are any discs or USB devices inserted into the PS3, remove them and try turning on the console again.
***Boot into safe mode***: Try booting your PS3 into safe mode by holding down the power button until you hear two beeps. From there, you can try restoring the file system or rebuilding the database.
If none of these steps work, it may be time to contact Sony customer support or take your PS3 to a professional repair shop.