Water got into my flatscreen tv. the volume plays but the screen is black. how can i fix this

You should never switch on any electronic device, when water seeps in! It can cause even explosion and human injury! If the temperature around can evaporate the water, just leave it idle for a few days. But remember to remove the plug from the power outlet. Alternatively, if you can remove the back cover, you can use a hair dryer and warm up the area where you suspect water has seeped in. But due care should be taken not to burn the PCB, plastic parts on the board or on the side. This is a case to be handled by a qualified service technician.