Terminology
Tosh,
1. Your computer is fine. (Usual caveats apply)
2. What is your definition of a 'Tiled Window'?
3. Do you have several programmes, or instances of a particular programme open at one time?
Without being next to you to see how you operate, it is difficult to diagnose your snagette.
If you have Word, Excel and Paint open, for example, they will be highlighted on the task bar. When a program is started, the application icon on the taskbar appears with a box around it. Multiple open windows appear grouped.
If Aero is enabled, moving the mouse over an application icon that is open will preview the window content straight from the taskbar. Lastly, right-clicking on application icon will pop up Jump Lists.
As to the wandering cursor, are you sure that you are not inadvertantly clicking 'off' somewhere?
PM me and I can send more info that you may find useful.