Windows 7: Camera on USB do not work

With my Panasonic camera and extern HD's all things work. However, when I connect my canon G15 or Nikon P300, the computer beeps, but does nothing. To open the device, I must go to 'device management', then to

'portable devices' and delete 'Canon G15'. Then I scan for 'hardware changes', Windows finds the G15 and installs the USB driver. Then I can open the map from the camera, and that works as long as the computer is on. When I restart the computer, it does not work anymore, and again I must re-install the driver.
Can someone please help me, this is very annoying!

Plug in the camera, then turn it (the camera) on. You may have to click on Computer, then see your camera as "Portable Device", right click to import pictures.

But I do not see the camera, that is the whole point. I must reinstall the driver first, and then I see the camera and can do as you told.

After you plug the camera in and turn it on, do you see it in "Devices and Printers"? If not, click 'add device' and see if Windows will find it and place your camera there. Or, you may need to use another USB port to plug it into.

Then I see the camera, but with a yellow exclamation mark. And I have tried all the USB ports, I have even removed and reinstalled them!

You may want to consider spending a little bit of money on a card reader. Not only do they work better, but they don't use the camera's battery power to offload the photos.

I do have a card reader.

Most Camera's use an SDHC card to record the pictures/video. You can take the SDHC card out of the camera and put it into the card reader. From there you can save, edit, delete pictures. Then put it back in the camera.

What an original idea!