I'm trying to take pictures and record videos, but the lens is not responding to my actions through the camera.

I've plugged the camera in, but the battery doesn't seem to be gaining any life.

I've pressed the power button repeatedly, but the camera doesn't respond.

Your LCD screen might be broken or it may not be completely attached to the circuit board. Check out the LCD screen disassembly guide to verify if it's plugged in. If it still isn't working after you've checked this, then you'll need to buy a replacement.