My 18" Asus monitor is 3 yrs old. Lately, very small emerald green sparkling dots have been showing up on the screen. There is no particular order to them. Sometimes they are all over the screen and sometimes just in small areas. If I turn off the monitor for about 8 secs., they usually go away. Sometimes I have to repeat this operation 3 or 4 times to get them to disappear. Please help.