My proview 19 in turn on but then it goes black is it a capasitor and how to fix it or is ther a reset on it

It may be the internal backlight that is failing. You can take a flashlight and hold it close to the screen, move the flashlight all around the screen and check if you can see anything. The display will be dark, but you should be able to make out the image that is there with the flashlight technique. If you can see an image on-screen, then your backlight has failed and you will need to replace the monitor. Weather or not you see an image is not a critical issue, but a tool to verify if the backlight is off or some other issue is causing the problem.
Note, it may be difficult to detect an image on the un-light display, for example if you have a dark image as your desktop background. So make sure to fully scan your display (top to bottom, and left to right covering the entire screen) with the flashlight technique in order to see any image on-screen.