The Dell E171FPB is a 17-inch liquid crystal display (LCD) personal computer monitor. Problems with this model may come from the computer, the monitor, or the connection between them. A few troubleshooting steps can help determine the source of such problems.
Dell recommends switching off and disconnecting the computer from the monitor, then powering the monitor back on. It should show a box titled Self Test Feature Check with a list of four labelled colours. If it appears, the PC or the monitor cable is probably the source of your problems, rather than the computer.
Dell also indicates the E171FPB might show an error stating it can't use the current video mode. This occurs if someone sets the computer to an unacceptable resolution or refresh rate. Read the manufacturer specifications for appropriate rates, resolutions and other useful information.
In its troubleshooting guide, the manufacturer suggests resetting the E171FPB and pressing its Auto Adjust button when attempting to correct various problems. Auto Adjust often fixes problems like blurriness and pictures or text that run off the side of the screen.