TaskSwitch.exe
(Microsoft)
Microsofts enhanced Alt+Tab for Windows XP which is part of the Microsoft PowerToys for Windows XP. Whereas the standard Alt+Tab facility simply lists the names of opened programs that you can switch to, TaskSwitch goes further by showing a preview window of each program you can switch to with Alt+Tab.
Recommendation :
None. If you do not want this task, de-install the TaskSwitch PowerToy via "Add/Remove Programs".