Can't access photos on my iphone 4s

I have been able to sync my iphone with itunes with no problems, but I have never been able to access my phone through windows explorer to download photos. This problem is on my desktop computer (windows 7 pro 64-bit). I have connected my phone to my wife's laptop (windows 7 home premium 32-bit), and I have no problem accessing my photos, so I assume it is not the phone or the cable.

I have tried many things with no success, including using a different usb port, uninstalling/reinstalling itunes, all to no avail.

In device manager, I have tried uninstalling my iphone under portable devices, and apple mobile device usb driver (checking the box to delete the driver software). After scanning for hardware changes (or disconnecting reconnecting iphone), iphone shows up with a yellow triangle and exclamation point, and windows tells me that the driver installation failed. When I update the driver and point to the usbaapl64.inf file, it says it is successful, and then apple mobile device usb driver shows up under usb controllers again, but then windows reports the iphone driver failed to install (the error says the style of the INF was different than what was expected). If I try to update the driver for the iphone, and point to the usbaapl64.inf file, it tells me that "the folder does not contain a compatible software driver. If the folder contains a driver, make sure it is designed to work with windows for x64-based systems."

The driver it wants to install is MTP USB Device, but if I let it attempt to install that one, I just get the "style of the INF is different than what was expected" error again. I have tried stopping and starting the Apple mobile device service as well. I really have no idea what else to try.

Any help would be greatly appreciated!