Hover over Taskbar button to restore minimized application

Here's what I used to do. If i needed to open a new file in Photoshop, I would minimize it to the taskbar. Then I would then open a folder with my images/files in it (or from the desktop) I would left click any image/file and drag it to the minimized photoshop button on the taskbar. By hovering the image/file over the photoshop button on the taskbar for a second or two, photoshop would restore/maximize and I could drop the image directly onto the photoshop page.

Actually, any open program that was minimized to the taskbar could easily be restored by hovering a file over it.

This works on all my other computers, and used to work on this one, but has magically stopped.

It is a very handy technique to use, and since i have been using it for years, it is very annoying to have lost the ability.

Thanks in advance,
Elicitone

System info:

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows XP Professional, Service Pack 3, 32 bit
Processor: Intel(R) Pentium(R) 4 CPU 3.20GHz, x86 Family 15 Model 2 Stepping 9
Processor Count: 2
RAM: 3070 Mb
Graphics Card: NVIDIA GeForce FX 5200, 128 Mb
Hard Drives: C: Total - 409599 MB, Free - 194103 MB; D: Total - 476937 MB, Free - 168874 MB; F: Total - 544267 MB, Free - 529206 MB;
Motherboard: Dell Computer Corp., 0W2562