my finder column to the left disappeared. I don't know how to retrieve it. (the list of options such as "desktop," "documents," etc

And the simple solution: 'Alt-Cmd-S' to toggle the Navigation Column ;-)

Reboot

Try this:

With Finder active, click Finder in the menu bar and select Preferences. Next click Sidebar. Check (or uncheck) a few items, and close this window. You can go back to Sidebar to make sure you have selected everything you want.

And reset the NVRAM:

1. Shut down your Mac.
2. Locate the following keys on the keyboard: Command (⌘), Option, P, and R. You will need to hold these keys down simultaneously in step 4.
3. Turn on the computer.
4. Press and hold the Command-Option-P-R keys before the gray screen appears.
5. Hold the keys down until the computer restarts and you hear the startup sound for the second time.
6. Release the keys.

excerpt from: http://support.apple.com/kb/ht1379

If that doesn't work, in Finder hold down the option/alt key while selecting the Go menu item. Select Library. Then go to Preferences/com.apple.finder.plist. Move the .plist to your desktop.

Re-launch Finder by logging out/in and test. If it works okay, delete the plist from the desktop.

If the same, return the .plist to where you got it from, overwriting the newer ones.

If you want to make your user library permanently visible, run the below command in Applications/Terminal.

chflags nohidden ~/Library/

You will need to do that after any updates.

Have the same;

WORKAROUND: Go tot Finderpreferences / General and and select the HD in the "show in Finder-windows" in stead of Your home-window. (In general: select something other then 'Home' and 'Macintosh HD')