I should have elaborated. If the computer only has an Intel video chip, the only option to cure the problem is to add in another graphics board, if the computer can handle it.
Many OEM computers (Dell, HP,....) make use of a power supply designed to handle the load of the computer they built, requiring it to be replaced if a higher performance video card is to be added in. Some of the OEM's remove the ability for a video card to be added, which makes those computers, "what you see is what you get".
Dell will have all the options available to your computer.
First thing is to determine what video card/chip is in the computer. The symptoms sound very much like it has an Intel video chip.