If your computer screen goes something like…
or
or even
or, in fact, any colour abnormality/abomination on your screen, worry not, because it may simply be because of a loose VGA connector. VGA stands for Video Graphics Array. The VGA connector connects your monitor to your PC, is generally blue in colour, and looks something like…
The VGA connector uses separate channels for the three primary colours – red, green and blue (RGB anyone?). Anyway, when the connector comes loose, one channel may disconnect, but the others may continue functioning, so you’ll end up seeing only green and blue or something. You get my drift. You should use the screws on either side of the connector to fasten it to you CPU, if there are holes on your CPU female connector.
Trivia
VGA was also a video standard introduced by IBM in 1987. It ran at a resolution of 640×480. Now, it’s not much used in PCs but becoming popular in mobile media devices like cameras and video players.