Xs with WM or Desktop brakes? Clean installation.

[latinfo%vcn.bc.ca@localhost]

Hello

NetBSD-8.1

1. the Xs brakes when i try to use WMs or Desktop Mate and XFCE4, and how
to get out of Xs? Ctrl+Alt+Backspace do not work, pressing right button of
the mouse+exit does not work, it stay forever.

2. is there a simple form to start WMs or Desktops? i can not start Mate,
and others WMs and Desktop?

3. is there a simple command to delete all the packages (binaries),
installed by hand? something like: # pkg_delete everything or pkgin delete
everything? leaving only the NetBSD standard installation?

I have read the guide and How tos and Questions, but i could not find what
i need, could someone help?
thanks so much.