problem with network configurations

[jpugh@gladstone.uoregon.edu (enantiomer)]

Recently I looked into setting up my laptop so that it could switch
between static and dhcp.  I looked at an article on this group and
tried the suggestion and it didn't work.  I restored my interfaces
file back to normal (i had commented out what I had put in before) and
thought all would be well, but now it doesn't seem to like even my old
static ip network anymore.  I tried doing some diagnostics by running
ifconfig and route, but they dont return any values at all.  I am
confused on what I might have messed up, as I was very careful to
return the file back to it's original state.  Any help?  Below is a
copy of what is in my file currently.  Is there any sort of reconfig
tool for the network in debian?  Anybody see what might be wrong? 
Also, what is the best way to be able to switch between static and
dhcp for me? Thanks for the input!
  Enantiomer

-----------------------File begins below line -----------------------
# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)
# The loopback interface

#the first network card - this entry was created during debian
installation

#(network, broadcast and gateway are option)

iface eth0 inet dynamic
  address 192.168.1.22
  netmask 255.255.255.0
  network 192.168.1.0
  broadcast 192.168.1.255
  gateway 192.168.1.1

---------------------------file ends above line-----------------------