unable to dock my tasks on the task bar when switching between tasks

I have been unable to dock my tasks on the task bar when switching between tasks, any suggestions? I have to go to the task manager to switch.

 

Are you saying when you click at upper right to minimize a task, it will not do so?

I have some guesses, but lets start here with an oldie but goodie from the remarkable MS-MVP Kelly Theriot: http://www.kellys-korner-xp.com/regs_edits/xp_taskbar_desktop_fixall.vbs

This is a vb script file, so double click and approve its running.

See also by Kelly: http://www.kellys-korner-xp.com/taskbarplus!.htm
Even the freeware version likely can sort the issue.