When you connect the 77 to the computer the PMB starts and you should see something like 'Gps data update'.
Once done go outside and set the Gps in the camera on, be sure not to be near radar and cellphone/radio towers, power lines,, try to find an open field with free view to the sky, avoid (urban) canyons.
Don't stick your head between the gps and the sky, or cover it with your body.
.With new data loaded you should have a sat lock in a few minutes.
If you have VERY heavy clouds, your sats might be not visible on that moment.