iPhone is not recognised by iTunes, but is by Windowns 7.

I had this issue before. Uninstall iTunes but keep any data related to your iTunes collection (these will pop up during the uninstall process). Install the latest iTunes (10.7) and should be back to normal. This is usually caused by some services that may have stopped that wouldn't restart in Win7.

Make sure also that you install the correct Windows 7 install of iTunes. If you have 64-bit, make sure to use the 64-bit installer for iTunes.

Are you syncing through wireless sync or directly through USB?

There is definitely a conflict coming from somewhere. I would double check these steps to make sure. I provided a couple of KB articles below:

http://www.apple.com/support/iphone/assistant/itunes/

http://support.apple.com/kb/TS1363

or

http://support.apple.com/kb/TS1538

I remember that I had to go through Programs and Features in the control panel to uninstall everything that deals with iTunes also (Apple Update, iTunes, iPod Service, Apple Mobile Device Service, etc.). Pretty much got rid of everything except for QuickTime. Reinstalled iTunes, and was back in business. Sometimes it helps restarting the PC after install to apply settings.

I'm sure that you have follow most of these steps already and can be frustrating. Just need to make sure all our T's are crossed.

I Fixed this today by rebooting my computer. It was windows of Course!

Wish i had OSX

@arecapp Agreed. I have two Windows machines and they are horrible running iTunes and getting everything to sync up correctly. I'm saving for a replacement laptop soon and going MacBook Pro this time around. Tired of having to reload Windows every 6 months.

Wow, this is crazy. Have you tried a Windows restore point to before the issue happened?

Okay, here we go. There are couple of things that we need to check.

Plug your iPhone or iPod into a USB port in the back of the PC. (If its a laptop, any one will do, just not though an external USB hub)

Right click on an open area of the taskbar and click on "Start Task Manager" (You can also get to this by using CNTL+ALT+DEL)

When we get to a window that pops up for the task manager there are some things we need to see if they are running. Click on the services tab and sort the services alphetically by name and look to see if the services below are running.

1. Apple Mobile Device

2. Bonjour Service

3. iPod Service

If one of these above are not running, there is an issue with the service. Right click on the service above that isn't running and click "Start Service" on the context menu that pops up.

Unplug the device, exit iTunes, start iTunes, and then try to sync the device.

(I had to break my iTunes to really figure out a good process)

I have the exact same issue. I have done every single thing suggested, short of buying a new PC! I reformatted my laptop tonight and that didn't help.

It's getting really frustrating now. I hope someone can think of something else to try!

Do the drivers appear in your device manager correctly?

They should appear in the universal serial bus controller section labeled as "Apple Mobile Device"

I have this exact problem too. I have done exactly the same steps as above and still does not recognise the devices.