Hi Rob,
I'm new to Windows 7 so I can't offer any specific solution but I can make a general suggestion.
Most entries in the Windows Start menu and on the Windows desktop are actually "shortcuts" that point to a program or file. If you right-click on a shortcut and choose "Properties" from its popup menu, you'll see a tab called "Shortcut" in the Properties dialog box. It contains a "Run" setting with a dropdown list where you set the window mode for the program. Most of the time it will be set to "Normal window" but you'll see that one of the options is "Minimized". If you select "Minimized" then each time the program is launched with this shortcut, it will immediately minimize to the Windows taskbar.
Now the question is: What is causing PowerDVD 9 Ultra to minimize when you indirectly launch it by loading a DVD? Perhaps Windows 7 has a "Run" setting for programs the same as earlier versions of Windows have for shortcuts. I would start by looking at the properties of the PowerDVD 9 Ultra application, itself, and see if Windows 7 offers a property that controls the window mode.
Kind regards, David