Hi,
1. Did you make any recent changes to the system prior to the issue?
2. Are you able to boot in safe mode?
3. What type of installation do you want to perform?
4. Is it a clean installation or a repair installation?
5. Why do you want to perform a re-installation?
6. What is the exact issue that made you to decide a re-installation?
If you are referring to perform a factory restore settings, I would suggest you to contact Dell Support for further assistance.
Hope it helps.