Same problem here. When I use the VGA cable, then I'm able to get 1024x768 resolution only. But when I use a DVI cable, then the screen goes black. But when its booting up, then the boot info of Windows appear on the same screen suggesting that there is no connection issue.
If you have intel Graphics Media Accelerator (integrated Video on the chipset), it will do it, as it's got a limit of memory for video. If you have NVIDIA or ATI video, then, try updating drivers from dell.com, to overwrite them, as they might be wrong.