Hi, thank you for using JustAnswer.com. I am glad to assist you today.
First, make sure that there are no CD or DVD in the optical drive. ALSO, please make sure that all USB devices attached to the laptop are unplugged especially Flash Drives and external hard drives.
After this, try booting or starting the computer normally and see if it works this time. If not, please do the next steps:Do System Recovery
There are two ways to load the System Recovery to reset your computer to factory default.
1. Press Ctrl+F11
If you want to restore your system back to the way it was shipped, when the system boots, immediately press the Ctrl key and F11 keys at the same time and you will enter the Dell Recovery Restore Utility.
This process however wipes your hard drive clean so your data will be lost. You should have a working backup to restore the data from after the recovery.
After you enter the Dell Recovery Restore Utility, just follow the instructions and the restore should complete in approximately 15-20 minutes, depending on how much data is to be restored and the speed of the computer.
If Ctrl + F11 (Hold Ctrl key, then press F11) won't bring up the Recovery utility, please try pressing 0 (that is the number ZERO) instead and see if the recovery starts.
I hope that helped.