Taskbar Minimize / Maximize buttons won't display

Something's gone south with my setup of WIndows XP SP2. The Taskbar
buttons for open applications, which you can then minimize or maximize,
won't display. When I minimize an application, they disappear off the
screen, but do not leave memory. Bringing up the Task Manager allows me
to restore the application to full screen.

The problem occured after I installed Windows Desktop Search Version 3.
I removed Desktop Search via the Control Panel, but the issue remains.
I assume this is some kind of registry setting problem.

Reference Microsoft article 555512

I tried re-setting NoVisualStyleChoice to "O" but this had no effect.

gpedit.msc is not available from the run command

This is an essential feature for my PC and I would like to get it back.
Please advise. Thanks.


.