Switch between windows back

Hello, please anyone can post me keystroke commands for switching back?

forward is done easy with hotkey command. but backward?

the key combo is: strg + shift + tab.

In what application?

hi, simply between windows xp windows.

thanks

Ctrl (or strg in German) + shift + tab does not switch from one application window to another, it switches between the windows of the same application and it already does it backwards.
You should use alt+tab or win+tab for switching between applications, and alt + shift + tab or win + shift + tab for reverse respectively.