Once my xp home edition 'all programs' appeared on the whole screen, now it is appeared in one row. How I can changed it back to the original appearance.

You can hit the double arrows at the bottom, this will expand it out. The defaul is to only show you programs you have recently used.

There should be an option in themes?

Right-click onn the Start button, select Properties, in the Start Menu tab the dot is probably in "Classic Start Menu", clikc on the radio button for "Start Menu" to get the "All Programs" look you want.