Turning on issues, showing grey screen

@shaury19662 this can happen when your computer can't find the OS. Possibly due to a failed hard drive. Try to enter the BIOS and check if your HDD is still detected. Press the F2 key several times at the Dell logo screen during startup to enter the BIOS. If the BIOS can't find your HDD, I would create a bootable USB drive with a Live version of Linux (I use Puppy Linux). Then set the boot order to USB and boot from that drive. Now use the Linux drive to see if you can access your HDD to at least recover your files. After that you would need to replace the HDD and reinstall your OS.

Of course, all of this might change once you start looking into the troubleshooting. Let us know what you find so we can continue to assist you with this.