Use Keyboard Shortcuts to Access Taskbar Items in Windows
In Windows 7 and 8, each of the item that you pin on the taskbar is associated with a shortcut. This allows you to quickly access the icon. The keyboard shortcut associated with the taskbar icon is "Windows key + number from the left". For example, if Windows Explorer is pinned as the first icon in the taskbar, pressing "Windows key + 1" will launch the Windows Explorer app.