Monitor flickers I installed UBUNTU and now the monitor has a high speed flicker, and I don't know what to do about it

flickering on the screen typically means that your screen refresh is too slow. I found this for you:
How to see change screen refresh rate or monitor frequency

If you wish to get some details; visit the site linked here. Pull up older posts. http://electronicshelponline.blogspot.com/ Line faults & possible causes to LCD & Plasma screen are given with illustrations. You can get an idea about the fault to an extent. Faults to all LCD & Plasma screen are similar, irrespective of its brand and screen size.

HDMI has the tendency to flicker on cheaper cables that don't have a strong connection. Try a different cable and see if it helps.

Flickering screen is often caused by a defective cable. Check all the cables attached to your monitor.
If you think all your cables are in good condition, the problem is probably with the environment. Monitors are sensitive to magnetic fields. Change the position where you have your laptop.
The problem might also be caused due to refresh rate not properly being set. In this case your screen will flicker when you open images or videos. Just adjust the refresh rate that will be available in graphic properties.
If the above solutions don't work, you probably will have to change your display.

Flickering on the screen can be caused by defective hardware in the computer or by improperly installed software monitor may flicker and goes into rolling state due to dust, overheating after a long continuous usage,loose circuitry or due to some electromagnetic interference with other like tv , UPS, large speaker systems etc.

FIX :

1.Try Re-installing your Video driver

2 If it is possible, connect a different monitor to the computer. If the flickering disappears, it is a fair indication that the monitor is defective, otherwise go to the next step.

3. Set up the computer and the monitor on a different place in your house. If the flickering disappears now, it is most likely an interference caused by something in the original location. Check for devices which can cause interference.

4. If the flickering persists, check the setup of your system. If available in the setup, make sure that the option Monitor Type is configured as Colour Non-Interlaced.

If you don't think any above possible reasons for the rolling or flickering state of your monitor then we recommend you to get your monitor checked by the monitor company at their respective service cente

Sounds like you have dislodged the monitor cable. It can be reseated by removing the screen bezel and the section above the keyboard, and ensuring that the connections are tight.

If it's still flickering after rechecking the connections, then you may have damaged the cable or connections.

Separate video chip - Ati9000 with 32MB discrete video memory - but onboard : soldered in there. It can't be replaced.

Good morning, afternoon, evening or night; whatever time of day you are viewing this solution post. Thank you for choosing FixYa to answer and solve your problem. Your Compaq MV520 Monitor is always blinking every time you turn on your computer and you want to know how you can fix it? First, we need to troubleshoot the problem. I'm thinking you probably need to refresh the flicker rate on your monitor. The flicker rate is probably set on a low setting, which is causing you screen to blink (flicker). This can be bad for your health as well because it can cause eyestrain and headaches. Your monitor is a CRT (Cathode-Ray Tube) model. These types of monitors can cause a lot of screen flickering. Now that we've troubleshooted the problem, now it's time to solve the problem. There are two ways you can solve this problem. You can either refresh the flicker rate or you can buy an LCD monitor. LCD monitors flicker-free. My suggestion is that you refresh the screen flicker rate. To refresh the flicker rate, go into your System Preferences or Control Panel, click your operating system's appearance and display link and click your screen adjustment link. You may have to click your advanced settings link. Click your monitor tab and from there adjust you screen refresh rate. You may have to adjust your screen resolution before you refresh the screen rate. If you have to do this, make sure the screen resolution you choose supports you monitor's height and width as well as visibility. The higher the resolution, the higher the screen rate. The instructions I'm giving you may sound like this because I'm not sure what your operating system is. I'm not to familiar with Mac Operating Systems, but if you have a Windows Operating System and you need better detailed instructions, just reply back. I hope this decreases your screen flickering and gives you a better viewing experience.

1.your video card driver must have crashed try re-installing it !!

or

2.your video card must have failed !!try connecting your laptop to a CRT or LCD monitor and check it out !!! if you get the same thing in your CRT then its your video card change it if you want!!

Your monitor supports a maximum resolution of 1280 x 1024. If windows fails to give you the option of changing to this resolution and those below it then please follow these suggestions:

Update your video card drivers, if you don't know the manufacturer of your video card try windows update.

Install the latest drivers for your monitor as well.
Your monitors driver click HERE