Windows 7 Taskbar View

I have two Dell windows 7 professional desktop machines. Both machines run Windows 7 professional with IE 11. The task bars at the bottom of the screen display differently between the older and the newer machine on the desktop. As an example, holding the pointer on the IE Icon on the older machine will bring up a vertical list of all the active IE sessions (Which I like). On the newer machine, pointing to the IE Icon will display a horizontal row of small screens of each active IE sessions. If I have more than one word file open, and I move the pointer to the Word Icon, I get the same effect, showing a horizontal row of small word screens. I have not been able to change the way the display works on the new machine so it is the same as the older machine. I prefer to see a list of active screens instead a horizontal row of mini screens.
How can I change this view?
Your help would be appreciated very much.

Charlie

Thanks for your assistance. With your help I was able to resolve the problem by going to Preferences under the Control Panel, and changing my selected Theme from Aero Theme Windows 7 , to Basic and High Contrast Windows 7 basic.

Charlie