Now is the time you need Recovery Media--a windows 8 disk, the thumb drive you made or should have made to boot when the computer won't boot or a  windows 8 install disk made from a downloaded iso file--any version of windows 8. If you are under warranty, request installation media from Dell.

BUT--First you have to be able to boot to the cd drive. You should have tried this long ago just to make sure you could do it. Put a disk in the cd-dvd drive and reboot the computer. As soon as you reboot start tapping F12 and keep tapping without waiting for any screen to get to the Boot menu and select the cd drive--or if the Repair/recovery option appears, select that instead.  You will get an error if the disk is not bootable, but that's ok. Just shutdown the computer after removing the disk. If you need an install disk try this--

A complicated workaround is to download the free trial of win 8 Enterprise iso file and burn it to a dvd on another computer using the 'burn disk image" selection when right clicking on the iso file. DO NOT install Enterprise, but boot to the dvd, select your language and choose Repair Windows on the next screen. 

booted from the disc but when i tried to do a repair it said the HDD is locked.

anyone ?