First thing to check is the cable. Maybe toss a different one on there just to be sure. If this fails, try hooking it up to a different monitor and see if the problem persists. If this fails, try some driver rehab. Uninstall the current drivers, reboot, install drivers again, reboot. AND if this fails, it is time to start looking at a new graphics card, or send in your current one if it is still under warranty.
Thanks for the replies. It just happen yesterday. Especially is very irritating when i want to watch movies. vertical lines. i unplug and plug in many times already seems like the same but sometime if i am lucky nothing appear.
Is a pretty old machine, 3years old.
AMD Phenom(tm) II X4 955 Processor,3200Mhz,4 Cores,4 logical Processors
ATI Radeon HD 5700 series
internal 500GB and 2tb, external 1tb
Samsung, 1980 x 1080
Creative gigaworks T3
Power Supply Unit
a good idea as lhaskew said would be to try a different monitor on this machine to see if its the monitor thats the issue...if the problem is still there with the new monitor then the pc or cable is the issue you could also try a different cable to make sure its not that....the purpose is to eliminate everything until you find what is causing the problem then hopefully we can fix it.