Sync your iPhone with your new PC can be tricky, because if you try to sync to a second PC directly it will complain you that you are already syncing with iTunes in another PC. Here I am going to tell you the easiest way I know to sync with the new PC without losing your music and data.
1. Copy data from the PC your iPhone is syncing with
If you only want to sync with the new PC, you need to copy the following directory to the corresponding directory of the new PC. Assume your user name in the PC is “USERNAME”, you will need to replace it with your real user name.
If you also want to transfer the music and data, you need this directory also.
2. Download and install iTunes in your new PC
3. Open up the iTunes in the new PC and authorize sync