LCD disturbances

I have downloaded the liquid crystal library from arduino(inbuilt come with arduino software) and run it on 20X4 alphanumeric LCD, its all ok but some time the display got disturbed like it shows some garbage data like chinese words and some times LCD’s 2nd and 4th line got dark and 1st and 3rd line clears but at this time controller operates as its normal operation i,e. internally controller do execution for LCD but LCD dont shows it.
I could’t understand whether it is software problem or hardware problem.

Because it goes normal by power reset not by controller reset.

Please reply.

Thanks in advance

... but some time the display got disturbed ...

What else is happening in the vicinity? Are there relays being energized, motors being started, etc.?

I could't understand whether it is software problem or hardware problem.

Neither can we without seeing your hardware and software.

Because it goes normal by power reset not by controller reset.

There is no way to reset the controller by means other than software. When you cycle the power to the Arduino it reruns the LCD software and thus resets the LCD.

Don

Hii thanks for your valuable reply i used i tried many things like lcd.clear(); function but when disturbance happens this clear(); function is also fails...i read some where that if u grnd D0-D3 possibly problem is solve ....is it right way to do this?? Other question is i only use arduino mega and 20x4 lcd nothing more than that ...and my power supply is laptop USB only...do u prefer me any good suggestions so i can try for remove this problem.??

When I first started using LCDs I had similar issues. It was always my wiring. How do you have it wired?