Right mouse click the desktop>Properties>Settings>Advanced>in the new window that pops ups choose Monitor> and making sure that you have the box checked to not allow modes not supported, chose the highest refresh rate that you can.
Changing the refresh rate might help, but it sounds like the real culprit is electical interference either from noise on your AC power line or RF noise being radiated thorugh the air from some nearby device.
sometimes i can see blocks of lines running down the screen
If you're trying to describe rather wide horizontal bands that slowly crawl down your screen, those are roll bars, probably induced by something dumping "hum" onto your power lines. Try moving the computer to an outlet on a different electrical circuit, and consider suspects such as large appliances, microwaves, or light dimmers; all of these can induce interference. If the bars appear intermittently, see if they coincide with such a device turning on.
Flickering and other screen fluctuations can be caused by nearby electromagnetic fields. Speakers or telephones placed too close to the monitor are often the cause of this. If you have no such devices close to the monitor, see if relocating/reorienting the monitor minimizes the interference; you might be able to pinpoint the source of the problem that way.
what do you mean by "probably induced by something dumping "hum" onto your power lines"? and by the way, this computer is in office. not home. so are the solutions given to me still relevant?like the microwave and refrigerator stuff...
what do you mean by "probably induced by something dumping "hum" onto your power lines"?
Depending on your part of the world, your AC power operates at a frequency of 50 or 60 cycles per second. However, some equipment (especially equipment with electric motors like refridgerators, elevators, power tools, etc.) generate other frequencies when operating, which can "backfeed" down the power line and mix in with the power feeding other devices on that power line. The result is that these frequencies combine with the frequency of the AC feed to produce unwanted voltage/current frequency fluctuations, which can affect the performance certain devices. In the case of televisions or video monitors, the interference often mainifests itself as visible "bars" which slowly creep up or down the screen. In the case of audio equipment, the result is usually an audible hum or buzz emanating from speakers or headphones.
and by the way, this computer is in office. not home. so are the solutions given to me still relevant?like the microwave and refrigerator stuff...
Even more relevant, because you probably have no control over, or might be totally unaware of, any changes or additions your company makes to your environment. Additionally, being an office environment, there will obviously be many more possible sources of the interference than there would be in your home.