Help! My MacBook Pro suddenly began running very slowly.

Question

Could someone help? All of a sudden, my MacBook Pro began running very slowly. Here is a  report I ran:
EtreCheck version: 1.9.15 (52)
Report generated October 8, 2014 12:32:34 PM PDT
Hardware Information: ?
  MacBook Pro (13-inch, Mid 2012) (Verified)
  MacBook Pro - model: MacBookPro9,2
  1 2.5 GHz Intel Core i5 CPU: 2 cores
  4 GB RAM
Video Information: ?
  Intel HD Graphics 4000 - VRAM: 384 MB
  Color LCD 1280 x 800
System Software: ?
  Mac OS X 10.7.5 (11G63) - Uptime: 0 days 14:39:59
Disk Information: ?
  TOSHIBA MK5065GSXF disk0 : (500.11 GB)
  S.M.A.R.T. Status: Verified
  disk0s1 (disk0s1) <not mounted>: 209.7 MB
  Macintosh HD (disk0s2) / [Startup]: 499.25 GB (468.87 GB free)
  Recovery HD (disk0s3) <not mounted>: 650 MB
  MATSHITADVD-R   UJ-8A8 
USB Information: ?
  Apple Inc. FaceTime HD Camera (Built-in)
  Apple Inc. Apple Internal Keyboard / Trackpad
  Apple Computer, Inc. IR Receiver
  Apple Inc. BRCM20702 Hub
  Apple Inc. Bluetooth USB Host Controller
Thunderbolt Information: ?
  Apple, Inc. MacBook Pro
Problem System Launch Agents: ?
  [failed] com.apple.coreservices.appleid.authentication.plist
Launch Daemons: ?
  [loaded] com.adobe.fpsaud.plist Support
  [loaded] com.microsoft.office.licensing.helper.plist Support
User Launch Agents: ?
  [loaded] com.google.keystone.agent.plist Support
User Login Items: ?
  iTunesHelper
Internet Plug-ins: ?
  Silverlight: Version: 5.1.20125.0 - SDK 10.6 Support
  FlashPlayer-10.6: Version: 15.0.0.152 - SDK 10.6 Support
  Flash Player: Version: 15.0.0.152 - SDK 10.6 Support
  QuickTime Plugin: Version: 7.7.1
  JavaAppletPlugin: Version: 14.9.0 - SDK 10.7 Check version
  SharePointBrowserPlugin: Version: 14.4.4 - SDK 10.6 Support
Safari Extensions: ?
  Pin It Button
Audio Plug-ins: ?
  iSightAudio: Version: 7.7.1 - SDK 10.7
iTunes Plug-ins: ?
  Quartz Composer Visualizer: Version: 1.3 - SDK 10.7
User Internet Plug-ins ?
  CitrixOnlineWebDeploymentPlugin: Version: 1.0.105 Support
3rd Party Preference Panes: ?
  Flash Player  Support
Time Machine: ?
  Time Machine not configured!
Top Processes by CPU: ?
      3% WindowServer
      0% Activity Monitor
      0% activitymonitord
      0% SystemUIServer
      0% configd
Top Processes by Memory: ?
  176 MB Safari
  106 MB WebProcess
  57 MB Finder
  49 MB mds
  45 MB WindowServer
Virtual Memory Information: ?
  2.24 GB Free RAM
  832 MB Active RAM
  386 MB Inactive RAM
  579 MB Wired RAM
  292 MB Page-ins
  0 B Page-outs

Answer 1

Launch the Console application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Console in the icon grid.
The title of the Console window should be All Messages. If it isn't, select
          SYSTEM LOG QUERIES ▹ All Messages
from the log list on the left. If you don't see that list, select
          View ▹ Show Log List
from the menu bar at the top of the screen. Click the Clear Display icon in the toolbar. Then take one of the actions that you're having trouble with. Select any messages that appear in the Console window. Copy them to the Clipboard by pressing the key combination command-C. Paste into a reply to this message by pressing command-V.
The log contains a vast amount of information, almost all of which is irrelevant to solving any particular problem. When posting a log extract, be selective. A few dozen lines are almost always more than enough.
Please don't indiscriminately dump thousands of lines from the log into this discussion.
Please don't post screenshots of log messages—post the text.
Some private information, such as your name, may appear in the log. Anonymize before posting.