If you want to sync some devices in Windows 7 using the Sync center you’d first have to enable offline files.
Using Offline Files
1. Step Open the Start Menu and click the Control Panel link
2. Step On the top right select Small icons from the dropwn
3. Step Find the option Sync Center and select it
4. Step On the left hand you can find the option Manage offline files
5. Step Finally, click the button Enable offline files, confirm the UAC prompt and hit Apply
6. Step You have to reboot to activate Offline files and sync offline files using the Sync Center