Unable to sync iPhone 4 with iTunes 10.6.3

My old computer crashed and I'm not on a new PC with Windows 7 Home Premium 64-bit.

I installed the latest iTunes successfully, but found that my iPhone 4 is now not syncing with it.

It can detect the phone, but it's not adding or deleting anything - apps, music or photos.

I used to be able to select a Photo Folder to sync from the PC hard drive, but now it no longer works.

There is no error message, the sync and backup apparently goes on, and then iTunes says it is searching for which apps to install but nothing happens to changes. Even when I've clicked Apply.

I've also tried closing iTunes and I've rebooted the phone but no dice.

Any help or advice would be much appreciated!