I have downloaded hundreds of photos from my Canon Powershot 85 to my Windows 7 Laptop but all of a sudden it stopped recognising the camera and doesnt open the download/display screen. In the morning it was OK and in the afternnon not so. I did download some photos from an Iphone yesterday so the Laptop must be working. Is there a camera setting I have inadvertently changed or what.
It could be your driver file is corrupted. Go to "Device Manager" (just search in the win7 start menu). Look for your camera's driver in the list of devices, (make sure you clicked show hidden devices, since disconnected device is often hidden). Then remove the old driver completely, then re-connect your camera.
Also try if your camera works on other computers, if not, then it's probably a hardware problem.