Compaq FP 5315 Moniter

Have you checked the computer bios?

 

In case an item was changed in the BIOS, such as the primary display device setting, use the following steps to reset the BIOS back to its default configuration:

1. Turn on the computer and press the keyboard key that enters the BIOS Setup screen key when the keyboard light comes on. The key to enter the BIOS should be one of the following:
   • HP and Compaq desktop computers that came with Windows Vista, press F10 .
   • For HP Pavilions desktop computers that came with Windows XP or previous versions of Windows, press F1 .
   • Compaq Presario desktop computers built after 2002, press F1 .
   • Compaq Presario desktop computers built prior to 2002, press F10 .
2. Wait 5 seconds.
3. Press the F5 key to restore the default settings of the BIOS.
4. Press Enter to accept the change and wait five seconds.
5. Press the F10 and then the Enter key to save the changes and exit from the BIOS.
6. The monitor should now display the first screens received from the computer (the logo screens). If not, find and download the latest BIOS update if one is available for your computer.
7. If a BIOS update was not available or the monitor is still blank, continue to the next step

Reseating loose internal components

If the PC case was recently serviced or moved, a card, cable, memory module, or processor may have become loose. When this happens, the PC might make a beeping sound when turned on. Use the following steps to check for loose components: WARNING: The edges of metal panels can cut skin. Be careful not to slide skin along any interior metal edge of the computer. CAUTION: This product contains components that can be damaged by electrostatic discharge (ESD). To reduce the chance of ESD damage, work over a non-carpeted floor, use a static dissipative work surface (like a conductive foam pad), and wear an ESD wrist strap connected to a grounded surface.

1. Unplug all cables except for the power. Write down each cable location if you do not already know where it connects.
2. With the power cable removed press the Power button on the front of the PC for 5 seconds.
3. Remove the screw(s) that retain the panel or cover from the rear of the PC.
4. Slide the side panel off from the rear of the PC.
5. Gently press down on the outside edges of cards and memory modules that are inserted into the motherboard to better seat them. Do not press too hard.
6. Gently press down on the connectors of the flat ribbon cables to seat them.
7. Replace the side panel and screw(s), reconnect the PC cables, and turn on the PC on.
8. If the monitor still displays a black screen, the video hardware may be faulty and needs to be replaced or serviced. If the monitor displays the first startup screen but does not display Windows, continue to the next step.

Try this and if it doesnt work. please post again.