How to stop a completely unresponsive software update

Question

Hey Apple Discussions,
I'll try to make this one as short as possible. I've tried to install the Safari 7.0.6 update. The download finished a while back, but I'm stuck with this:
It has not moved for the past day, and yes, I've tried turning the machine off and on again. (Why do people always ask that?)
Force quitting through Option-Command-Escape does not work, and I can't find a related system process I can quit (that still might be an option, I just haven't gotten it to work yet). Are there any terminal commands you could suggest? Thanks!

Answer 1

Back up all data. Quit the App Store application if it’s running. Test after each of the following steps until the problem is resolved.
Step 1
Triple-click anywhere in the line below on this page to select it:
/Library/Updates
Right-click or control-click the highlighted line and select
          Services ▹ Reveal
from the contextual menu.* A Finder window should open with a folder selected. Move the contents of the selected folder to the Trash. You may be prompted for your administrator password.
*If you don't see the contextual menu item, copy the selected text to the Clipboard by pressing the key combination  command-C. In the Finder, select
          Go ▹ Go to Folder...
from the menu bar and paste into the box that opens by pressing command-V. You won't see what you pasted because a line break is included. Press return.
Step 2
Do as in Step 1 with this line:
/Library/Preferences/com.apple.SoftwareUpdate.plist
Restart the computer. If there's no change, quit the App Store and restore the file you moved from your backup, overwriting the one that may have been created in its place. Otherwise, recreate your settings in the Software Update preference pane.
Step 3
Hold down the option key and select
          Go ▹ Library
from the Finder menu bar. Move the following items from the Library folder to the Trash (some may not exist):
          Caches/com.apple.SoftwareUpdate
          Preferences/com.apple.SoftwareUpdate.plist
          Preferences/ByHost/com.apple.SoftwareUpdate.*.plist
          Saved Application State/com.apple.SoftwareUpdate.savedState
Here, * stands for a long string of letters, numbers, and dashes.
Step 4
Restart the computer in safe mode. Certain caches maintained by the system will be rebuilt.
Safe mode is much slower to start up than normal. The next normal startup may also be somewhat slow.
When the login screen appears, restart as usual (not in safe mode) and test. There's no need to log in while in safe mode.
Note: If FileVault is enabled, or if a firmware password is set, or if the startup volume is a software RAID, you can’t start in safe mode. In that case, ask for instructions.