Top bar went AWOL

I get the following window when booting up, just after user login, just as icons populate desktop:

"Cannot start the preferences application for your window manager

Window manager "unknown" has not registered a configuration tool"

It all started when I was trying to strip out components of "wine" & I probably yanked out some essential stuff (yup, total newbie me!)

I had no window top bar with minimize/resize/close. The keyboard wouldn't allow me to type in some instances, especially on this page. Drop menus had to be done manually with arrow keys & escape to exit a window. No borders to adjust a window's perimeter were present & the scroll up/down would be hidden on some features & visible others.
I rebooted last night & had a recovery mode menu with things to the effect of "run in safe mode", "get rid of fragment packages" & somehow the problem fixed itself, at least for that session, it worked flawless. It started doing it again on next boot up. I researched forums & just did the command line "metacity --replace" & also put it into startup applications command, now it's back, seems to be working fine now. The part that gets me is how it "auto corrected" for that one session (& the wine stuff reappeared on applications menu as if I never took it out), then reverted to the top bar missing again. Bug?