Windows XP will group multiple open windows (IE windows, for example) into one group on the taskbar to keep the desktop clear. This can be annoying, especially when you are comparing different web pages because you have to go back to the taskbar, click on the group, and then click on the page you want. At this point, you only get one page because you have to click on each one separately. The default for this is typically eight windows in any combination of apps or utilities open.
You can modify this behavior by adding this registry key at the following location:
Change number of windows that are open before XP will start grouping them on the Taskbar
add reg_Dword “TaskbarGroupSize”
Modify “TaskbarGroupSize” entry to be the number of windows you want open before XP starts to group them on the taskbar. A value of 2 will cause the taskbar buttons always to group.