To help us assist you, please provide more information:
1) Decribe the issue you are having in detail. For example if its with a specific piece of equipment, include the make and model.
2) When was it working normally? Since then, did you add/remove any software or hardware?
3) What steps have you already tried to resolve the problem? (rebooted, searched google, etc)
My name is Kanika and I work for the Social Media and Community Team at Dell. It appears that there might be a problem with the video drivers as well hence in order to provide you with correct troubleshooting steps would suggest you reply to the question as asked by nhasian above on the thread. Also would request you to mention as what happens when you press the power button ; do u get the DELL logo / Windows Logo ??
In case you are able to logon to SAFEMODE WITH NETWORKING (by pressing F8 as soon as you power on your system)
would recommend you to reinstall the Video Drivers from the support.dell.com by selecting your system model.