iTunes not seeing iPhone. Windows 7

I'm wondering if anybody can help with the following.

I'm running Win7 Home 32-bit with all of the latest updates and also have the latest version of iTunes installed. I'm trying to connect an iPhone to my PC, via iTunes, but it is not recognised by iTunes, and I keep getting an error saying that it cannot read the iPhone.

However, the iPhone does appear in Windows Explorer (apparently as a camera, as I can read the DCIM file and look at the photos there), but as the iPhone is not jailbroken I cannot see any other files. The iphone is running iOS5.

From searching online, it appears that the problem may be that Windows thinks it is a camera, and has atatched a particular driver to it (an MTP driver). Others also suggest that I need to have the phone installed with a different driver (usbappl).(As suggested in http://support.apple.com/kb/TS1538)

If I uninstall the phone or try and automatically update the driver then it says that there is no better driver.

I have also tried to specifically update it with the usbappl driver (by updaing the driver and using the "have disk" option and then browsing to where the usbappl driver is installed). In this case I get an error saying that "the folder specified doesn't contain a compatible driver for your device).

Can anybody suggest how I can get Windows to update with the correct driver, or some other way of getting iTunes to see the iPhone.

Many thanks for your help.