IE7 and later will not automatically open links in a new tab in the SAME window. It will open multiple windows causing your system to use more resources. It may cause your system to run slower as well.
Not only is it more efficient to open links in different tabs in the SAME window, it also reduces screen clutter (too many windows open!).
It's easy to change IE7 to open links in different tabs in the same window.
Start IE7 and go to Tools --> Internet Options
Click OK to save your settings.