Windows 7 won't recognize my iPhone BUT iTunes will - can't access pics or videos, please help!

Hello!

I've been working on this for hours and am wondering if there's a simple fix. iTunes (version 12.1 64-bit) reads my phone just fine when I plug it in, but I can't get Windows 7 to recognize my iPhone 4S as an external drive so I can access/move pictures and videos from my phone to my computer. It seems to be a driver issue. When I first plug in, Windows tries to download a driver, but it is unsuccessful. The Apple Mobile Device USB driver seems to be installed and working correctly. It's the iPhone driver that is being a jerk. I've tried to reinstall the driver (code 18), which fails. Windows wants to default to the MTP USB Device, which Windows then says is not compatible for this platform. I've deleted all Apple programs to reinstall iTunes, thinking that the driver would correct on installation, no dice. I even tried to direct the driver to the usbaapl64 file under C:program files/common files/apple/mobile device support/drivers. This didn't work, either; I get a pop-up box saying that the folder doesn't contain a compatible software driver for my device. GAH!

It is worth noting that I have two 4S iPhones here and two computers running Windows 4S. Phone 1 works on Computer 1 as it should (iTunes and Windows 7 respond appropriately), but Computer 2 only recognizes Phone 1 in iTunes, not in Windows 7. Phone 2 is only recognized in iTunes on both computers: Computer 1 doesn't even try to download drivers, and Computer 2's driver attempt fails (see above). I've used different cables, different USB ports, and made sure that the phones trust the computers.

I would really appreciate any ideas or suggestions that you might have. Please help before I do something drastic and/or stupid. Thanks!