No display on monitor, 3 fast beeps when booting

Try a Hard reset!

1. Remove all connections from the computer including the power cable
2. Press and hold the power button for 20-30 seconds and then release
3. Only hook up the mouse, keyboard, monitor and power cable
4. Turn the computer

let me know what happens!

A one second beep from the computer is standard for a proper boot.
Do you have a TV that you can plug your computer into to see if it is posting video? That would be the easiest way to test if it is a computer or monitor thing.

James,
It sounds like the refresh rate is set to high. Since you do not mention what OS is installed I have listed information on how to change in Windows,XP.
Start the computer and press the F8 key. Choose Safe Mode. Once the system gets into Windows follow the steps below and then restart the computer. If this does not resolve your issue email me at my email address below and include your OS information.

How to Change the Screen Refresh Rate of Your Monitor

1. Click Start, click Control Panel, click Appearance and Themes, and then click Display.
   
   Alternatively, right-click the desktop, and then click Properties.
2. Click the Settings tab, and then click Advanced.
3. Click the Monitor tab, and then click the screen refresh rate that you want to use.

NOTE:

• The default refresh rate setting is 60 Hertz (HZ); however, your monitor may support a higher setting. Check your manufacturer's documentation for information about the settings that your monitor supports.
• If you use a higher refresh rate, you can reduce the rate that your screen flickers; however, if you specify a refresh rate that is too high for your monitor, your screen may become unusable and your hardware may be damaged.
• Changes to the refresh rate affect all users that log on to the computer.

Or your system is giving off a beep code in which case the beeps come in a 3 beep sequence. Below is the beep codes and what each represents.Beep Codes

Troubleshooting steps and more information about the OptiPlex 320 beep codes Beep Codes Code Cause 1-1-2 Microprocessor register failure 1-1-3 NVRAM 1-1-4 ROM BIOS checksum failure 1-2-1 Programmable interval timer 1-2-2 DMA initialization failure 1-2-3 DMA page register read/write failure 1-3-1 through 2-4-4 DIMMs not being properly identified or used 3-1-1 Slave DMA register failure 3-1-2 Master DMA register failure 3-1-3 Master interrupt mask register failure 3-1-4 Slave interrupt mask register failure 3-2-2 Interrupt vector loading failure 3-2-4 Keyboard Controller Test failure 3-3-1 NVRAM power loss 3-3-2 NVRAM configuration 3-3-4 Video Memory Test failure 3-4-1 Screen initialization failure 3-4-2 Screen retrace failure 3-4-3 Search for video ROM failure 4-2-1 No time tick 4-2-2 Shutdown failure 4-2-3 Gate A20 failure 4-2-4 Unexpected interrupt in protected mode 4-3-1 Memory failure above address 0FFFFh 4-3-3 Timer-chip counter 2 failure 4-3-4 Time-of-day clock stopped 4-4-1 Serial or parallel port test failure 4-4-2 Failure to decompress code to shadowed memory 4-4-3 Math coprocessor test failure 4-4-4 Cache test failure
Thank You,
Dell-Jesse L
Dell Social Media and Communities
email [email protected]

disconnect the power adapter and battery
2) make a HARD RESET 3) press the button power and hold by 60 seconds.
3) connect the power adapt +battery and try again.
4) if the problem persist. test the power adapter for short and repair or replace.
restart pressing the f8 and go safe mode with network, and RUN the scannow.
5) Run the software coming with the computer.too
God bless you

Thanks for the tip, good work.

Maybe one of your memory chips is bad.

If it seems to boot up all the way except the display is blank try the steps below:

Borrow a monitor from a neighbor, friend, relative or co-worker and connect it to the computer. If the Borrowed monitor display the desktop then the original monitor is bad, but the video card inside the computer is ok. If the Borrowed monitor does not display then the video card inside the computer is bad.

If it does not seem to boot up all the way try the steps below.

When you plug in the power cord is there any lights whatsoever on the laptop, where the plug goes in or on the AC Adapter of the power cord?

When you press the power button do you hear fans running, hard drive spinning, lights on the computer, hear any beeps or lights constantly blinking, hear the DvD/CD drive click and the light on the drawer of the DvD/CD turn on for a second or two? If so the computer is trying to boot or may have booted, but the screen is not showing for some reason.

Beep tones and blinking lights tells the technicians what is going on with the laptop and why it is not booting. Most times it's a motherboard issue when you hear beeps or blinking lights continuous. Most times the problem is with the memory or Video Card. Count the Blinking Lights or Beeps and take note of their pattern (1 Long or 1 Long followed by 2 Short).

Maybe you have a Static Charge Buildup. Remove the Power Cord, then Press and Hold the power button for 30 seconds. After 30 seconds plug the power cord back in and hit the power button to see if it boots.

Maybe your memory is bad or the memory slot is bad.

Remove the Power Cord, Open the Case and remove one of the memory chips. Set the chip aside then try rebooting the computer. If it boots, then you know the memory chip you set aside is bad so mark an x on it with an ink pen. If it fails to boot then move the chip to the next memory slot and try rebooting. If it fails take the chip out and set it aside, then put the other chip in and try booting it in both slots. If it boots, just to verify that the chip set aside is bad, mark an x on it and put it into the open memory chip slot and try booting.

If it seems like the computer completed the boot process but the screen is blank, try the steps below.

The problem will either be the monitor or the video card inside the computer. Connect another monitor to the computer to isolate the problem. Borrow a monitor from a neighbor, friend, relative or co-worker and connect it to the computer. If the Borrowed monitor displays and works ok, then your original monitor is bad and the video card is good. If the Borrowed monitor does not work then the video card inside the computer is bad.

If the computer did not complete the boot process then try the steps below.

When you plug in the power cord is there any lights whatsoever on the laptop, where the plug goes in or on the AC Adapter of the power cord?

When you press the power button do you hear fans running, hard drive spinning, lights on the computer, hear any beeps or lights constantly blinking, hear the DvD/CD drive click and the light on the drawer of the DvD/CD turn on for a second or two? If so the computer is trying to boot or may have booted, but the screen is not showing for some reason.

Beep tones and blinking lights tells the technicians what is going on with the laptop and why it is not booting. Most times it's a motherboard issue when you hear beeps or blinking lights continuous. Most times the problem is with the memory or Video Card. Count the Blinking Lights or Beeps and take note of their pattern (1 Long or 1 Long followed by 2 Short).

Maybe you have a Static Charge Buildup. Remove the Power Cord, then Press and Hold the power button for 30 seconds. After 30 seconds plug the power cord back in and hit the power button to see if it boots.

Maybe your memory is bad or the memory slot is bad.

Remove the Power Cord, Open the Case and remove one of the memory chips. Set the chip aside then try rebooting the computer. If it boots, then you know the memory chip you set aside is bad so mark an x on it with an ink pen. If it fails to boot then move the chip to the next memory slot and try rebooting. If it fails take the chip out and set it aside, then put the other chip in and try booting it in both slots. If it boots, just to verify that the chip set aside is bad, mark an x on it and put it into the open memory chip slot and try booting.

http://www.pchell.com/hardware/beepcodes.shtml

do you see the light blinking in the monitor? I mean the POWER led light up? If so, then the monitor is ok and is working good. It is your CPU which has a problem and not sending digital signal for the monitor to display.
Try to turn off your computer. After 3 minutes turn it back on. then notice if you will hear a short beep from the CPU. That signals a successful video initialization. If you went through that process, then your computer will get back to life.
However, if you dont hear a short beep from the CPU, then definitely your CPU is frozen therefore there is nothing to display to the monitor.
You need to open the CPU case, pull out memory modules then plug them back in. Then try booting.
If not successful, try to open case and pull out the processor. Put it back in after 30 seconds. Try booting again.
Do ALL THESE while your PC is UNPLUGGED.
Good luck.