Precision 7510 not responding

I'm using Precision 7510 for approx. 4 years now. The laptop usually has problems on-and-off but could be solved from time to time.

Recently it started having 100% CPU usage problem more frequently and utilizing solutions shared by online communities including updating Windows/drivers/etc. Those solutions worked a few times and the problem reoccured until last week no solution, as far as I have come across, worked anymore.

I decided to finally run the disk check (last option I opted as last time I did this it took me more than a day to finish). I chose to run the disk check after restart but after waiting for a day, it stuck at Dell logo screen. Now, upon pressing power button, the laptop couldn't get pass the Dell logo screen.

On power button press
- Power on
- CPU running for a few second then goes off
- Caps lock light is on when press

On F2 setting
- Tried reset BIOS, not working and got the black screen (waited hours, power on, CPU not running, caps lock light on when pressed)

On F12 one-time boot
- Tried diagnostics, not working and got the black screen (waited hours, power on, CPU not running, caps lock light on when pressed)

Any suggestion/solution, please help advising.

Thank you!