Hi, I have just purchased the lumix fz200 and have been using it for a week. I went to take some pictures yesterday and when I turned the camera on, I could not see out of the LCD monitor or the viewfinder - it is like the lense cover is still on. I can view pictures that I have already taken, but am unable to take any new pics (just a black screen). Can you advise? Many thanks

SOURCE: SCREEN AND VIEW FINDER BLANK

Is the battery dead? Try taking it out and charging it, then put it back into the camera.

Also, you can try using another battery of the same type.

SOURCE: Video playback problem on lumix dmc tz3

I don't have a solution to the first part of your dilemma (why it won't playback) but I do have a solution for deleting the file.  On your camera are "hidden" file folders.  When you connect your camera to your computer, you probably only see two folders (that's all I see for my DMC-LZ8).  But there are more, and your undeletable picture/video is in one of these folders.  Find the folder and you'll find the file.  Delete it from your camera using the computer to do the command.  Problem solved.  Okay, so how do you find the hidden folders?  I have a Mac, so my process was this:  1) Connect camera to computer; 2) Select/open camera icon (looks like "volume disk"); 3) From top Finder bar, select File then Find;  4) Select the camera volume to limit your search to the camera (not HD or other external hard drives you may have connected to your computer); 5) Select "Kind" and in the next dropdown button "Folders".  Voila.  Happy searching.  My hidden "undeletable" video files were in a folder called "100_PANA".  I selected them then moved them to the Trash.  Be sure to eject your camera properly (don't just turn it off or disconnect it).
Good luck.  I hope this helps.
PS - My theory is that this occurred after an upload to my computer got unexpectedly disconnected before everything finished loading or else the camera got disconnected from the computer incorrectly even if the upload had already finished (see above comment to eject camera properly).  In either case, the blank/black screen, unviewable but "there" on the camera taking up memory photos/videos problem happened to me, too.  The above actions resolved it for me.

SOURCE: unable to view pics from memory card of lumix camera

hi i think your memory card is dead, just to make sure try it in something else. let me know Yvon chow !!!

SOURCE: Panasonic lumix fx 10

If ECONOMY is set to off in that case monitor (LCD) would be brightest, it should not be dark, it would be at lowest if you set it to LEVEL2. Monitor sub-menu in the setup menu gives you option to increase or decrease brightness of the monitor (LCD).

SOURCE: Hi, I have a Panasonc Lumix DMC TZ2 digital

Sounds like you lost the connection to the sensor.