Administrator is missing taskbar/start menu
 

Here's an idea- It sounds like Administrator's local profile is corrupted,
to be quite vague about it. There's probably better ways to fix this, but
how about creating a new administrative user and logging on as that user.
Then you can copy out whatever you want to save from the administrator's My
Documents folder (This is IMPORTANT- the next steps will delete whatever
documents and settings have been created by administrator). Then just delete
the administrator's local profile. Look in Control Panel in System
properties, Advanced, User Profiles settings button to see a list of all the
existing user profiles. When you log in as administrator next time this
local profile will be rebuilt from the defaults. You have not deleted the
user from the system, just the user's profile.

This is a heavy handed solution, but it should work. You may just prefer to
use the new administrator-level account instead ...

good luck, Dave