Do you mean as a result of someone navigating on the menu, or do you mean as you are creating the menu?
If when building the menu, take a look at the selected/active/inactive color sets that are specified for the menu.
If you're looking at changing colors as folks navigate on the menu, then no. If the activate a button you could create a different menu that has the same layout but different colors, but DVDA doesn't support "on navigation" operations.
Under what conditions? You have a certain amount of control regarding the look of the button by using the inactive/selected/activated highlighting color set information. If you don't like the fact that all of your buttons are blue (regardless of whether they are inactive/selected/activated) then you'll need to create your own button using something like photoshop.
I am guessing that you have a color set that you like and want all your menu buttons to use it. This is what global color sets are for. select a color set that you are not using and change its type to global and set up the colors like you want. After this it will be available on all your pages as a global color set.
So if you set color set 2 for example to be global with settings of 120, 120, 120, 255 you will be able to use this color set for any object on any page of your menu.
Color sets only affect the highlighting, not the underlying picture (the arrow or whatever the graphic is). As already noted, if you want different colors for the arrows, you have to edit them in your favorite photo editor (e.g., Photoshop).
Most graphics are in the _themes folder of your DVD Architect installation (not to be confused with the "themes" folder without the underscore.)
c:\program files\Sony\DVD Architect 2.0\_Themes
You'll see names like "Arrow-Blue-Left.png" and "Arrow-Blue-Right.png." Those are the files you must edit (save the originals somewhere before you edit, of course).