To stop grouping similar taskbar buttons on the taskbar
1.
Open Taskbar and Start Menu Properties by clicking the Start button , clicking Control Panel, clicking Appearance and Personalization, and then clicking Taskbar and Start Menu.
2.
If Group similar taskbar buttons has a check mark next to it, the buttons will automatically stack on top of each other. To turn off grouping, click Group similar taskbar buttons, which clears the check mark.
Full detail on management of your Windows
HERE.
Posted Vista link, meant
WIN7 link. Sorry!