after you cut it on, or reboot it, the screen goes to booting up screen, then after that is goes black with a cursur blinking in top left corner and you cant do anything. When you press the keys it makes a beeping noise
try booting in safe mode it sounds like a video driver issue
when past the bios screen press f8
if it lets you boot into the desktop go to control panel and uinstall the drivers
restart and install the newest drivers (intel,amd,nvidia)
need more info... does it show dell post (dell logo) sceen... what are your led lights displaying, is the disk led light blinking, solid, off(if off your hdd maybe defective)? If you get dell post screen enter your bios check if it recognize hhd, mem, etc.
This happens to my Dell once in a while. Happens most often when I am hooked to an alternate display and I close the lid suspending the system, then re-opening without the alternate display hooked up. I force off (hold power button), reboot and then it resumes. Sometimes I just access the bios, dont change anything then exit and it will resume from when the lid was closed. Today when it happened Win 7 reported the audio driver failed to initialize but the troubleshooter took care of that.