Could be because it's 13 years old. 3 weeks ago the monitor screen started an occasional random blink that has become more frequent. Nothing in the adjacent environment has changed recently. The cable appears to be good. Video card? Gotta learn about that. Computer is G4 tower, Digital Audio, 733 MHz with Tiger. Any suggestions besides getting a up to date computer will be appreciated by this retiree on fixed income. For good measure I'll take the computer to the shop and clean it.