If your Windows is not synchronizing system time correctly, use these freeware to force Windows to sync time at every startup - NetTime, Atomic Clock Sync, Dimension 4.

Windows will now attempt to synchronize the time with the global time server. If your PC fails to update the time automatically, scroll down to Additional Settings and click on the Sync Now button.

In the Firefox menu bar on your main computer, click Tools and select Set Up Sync. The first time you do this, you’ll need to create an account with the Firefox sync server.