Help,my camere does not power on?

Follow the instructions on the screen.  I've been able to solve similar problems by pressing on the lens.  However, this was when the camera's lens was stuck in the extended position.  If your camera's lens is in the closed/retracted position, there's nothing you can do other than send it off for repairs that are likely cost $75-$150.

Stuck lenses are a common problem as it's easy for dirt to get in the gap between the lens and the main body.  Making sure your battery is fully charged is a good start but you might need to use a bit of GENTLE pressure on the lens.  If that doesn't work, google "stuck lens" and see what you fancy trying.  There's a good chance that having the camera repaired would cost more than replacing it!

Make sure the battery is fully charged (consult your manual).

If it's the Li-ion battery that came with the camera, and you're doing everything right, try a second battery.

It's only fair to point out that it's very rare for a camera to be charged from the computer - most need either a USB mains adapter, or a separate mains charger (the necessary bits should've been in the box when you bought it).