Install GNOME on Debian Wheezy 7 KDE
The Guide shows you Step-by-Step How to Install GNOME 3 Desktop on Top of Debian Wheezy 7 KDE4 Linux.
Inside to the How to Install GNOME on Debian Wheezy 7 KDE you will Find Links to
How to Install Lxde Desktop, Latest Firefox and Google-Chrome for Debian Wheezy.

Open a Terminal Window
(Press “Enter” to Execute Commands)In case first see: Terminal QuickStart Guide.
Install the GNOME3 Desktop on Debian Wheezy KDE4.
su -c "apt-get install aptitude tasksel"
su -c "tasksel install gnome-desktop --new-install"
During Setup you will be Asked to Set the Default Display Manager and If you Do Not Want to Remove KDE Just Leave the Default kdm.
Log-Out and Log-In Into GNOME.
Debian Wheezy KDE How to Install Lxde Desktop
How to Install the Latest Firefox on Debian Linux:
How to Install Google-Chrome Web Browser in Linux Debian