Help...I have no panels

[Albert Wagner]

After installing this mornings latest updates from Ubuntu, a restart was 
requested.  When the system rebooted, it had no panels.  I 
cntl-alt-deleted, then selected the failsafe option.  I now have a 
somewhat smaller image still without panels.  FWIW, I was messing around 
with Seahorse, keyrings et al yesterday.  What could I have possibly 
done to cause the loss of panels in both normal and failsafe modes.