Very slow Mac, EtreCheck result

Question

Hi. I have run an EtreCheck scan with the result below. Please tell me why my Mac is so slow and whether we need more RAM… We did have TimeMachine working but the external drive has suddenly stopped working (neither our Mac or Macbook can see it when plugged in) so we have to buy a new one hence the problem in that section.  Thank you for you help
Problem description:
Very slow Mac
EtreCheck version: 2.2 (132)
Report generated 4/25/15 12:04 PM
Download EtreCheck from http://etresoft.com/etrecheck
Click the [Click for support] links for help with non-Apple products.
Click the [Click for details] links for more information about that line.
Hardware Information: ℹ️
    iMac (27-inch, Mid 2011) (Technical Specifications)
    iMac - model: iMac12,2
    1 2.7 GHz Intel Core i5 CPU: 4-core
    8 GB RAM
        BANK 0/DIMM0
            4 GB DDR3 1333 MHz ok
        BANK 1/DIMM0
            4 GB DDR3 1333 MHz ok
        BANK 0/DIMM1
            Empty 
        BANK 1/DIMM1
            Empty 
    Bluetooth: Old - Handoff/Airdrop2 not supported
    Wireless: Unknown
Video Information: ℹ️
    AMD Radeon HD 6770M - VRAM: 512 MB
        iMac 2560 x 1440
System Software: ℹ️
    Mac OS X 10.7.5 (11G63b) - Time since boot: 6 days 0:51:46
Disk Information: ℹ️
    WDC WD1001FALS-403AA0 disk0 : (1 TB)
        disk0s1 (disk0s1) <not mounted> : 210 MB
        Macintosh HD (disk0s2) / : 999.35 GB (467.46 GB free)
        Recovery HD (disk0s3) <not mounted>  [Recovery]: 650 MB
    OPTIARC DVD RW AD-5690H
USB Information: ℹ️
    Apple Computer, Inc. IR Receiver
    Apple Internal Memory Card Reader
    Apple Inc. FaceTime HD Camera (Built-in)
    Apple Inc. BRCM2046 Hub
        Apple Inc. Bluetooth USB Host Controller
Thunderbolt Information: ℹ️
    Apple, Inc. iMac
Launch Daemons: ℹ️
    [loaded]    com.adobe.fpsaud.plist [Click for support]
    [loaded]    com.microsoft.office.licensing.helper.plist [Click for support]
    [not loaded]    com.palm.novacomd [Click for support]
User Launch Agents: ℹ️
    [failed]    com.apple.CSConfigDotMacCert-[...]@me.com-SharedServices.Agent.plist
User Login Items: ℹ️
    iTunesHelper    Application Hidden (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)
    Dropbox    Application  (/Applications/Dropbox.app)
Internet Plug-ins: ℹ️
    RL Secure Plug-In Layer: Version: Unknown - SDK 10.5 [Click for support]
    FlashPlayer-10.6: Version: 17.0.0.169 - SDK 10.6 [Click for support]
    Flash Player: Version: 17.0.0.169 - SDK 10.6 [Click for support]
    QuickTime Plugin: Version: 7.7.1
    SharePointBrowserPlugin: Version: 14.4.4 - SDK 10.6 [Click for support]
    Silverlight: Version: 5.1.10411.0 - SDK 10.6 [Click for support]
    JavaAppletPlugin: Version: 14.9.0 - SDK 10.7 Check version
User internet Plug-ins: ℹ️
    ContentManager: Version: Unknown - SDK 10.5 [Click for support]
    RocketEngine: Version: Unknown - SDK 10.5 [Click for support]
    UploadManager: Version: Unknown - SDK 10.5 [Click for support]
Safari Extensions: ℹ️
    Add To Amazon Wish List
3rd Party Preference Panes: ℹ️
    Flash Player  [Click for support]
Time Machine: ℹ️
    Time Machine not configured!
Top Processes by CPU: ℹ️
         2%    WindowServer
         1%    WebProcess
         1%    fontd(2)
         0%    SystemUIServer
         0%    Microsoft Word
Top Processes by Memory: ℹ️
    901 MB    WebProcess
    811 MB    Safari
    156 MB    iTunes
    156 MB    WindowServer
    98 MB    Microsoft Word
Virtual Memory Information: ℹ️
    811 MB    Free RAM
    7.21 GB    Used RAM
    26 MB    Swap Used

Answer 1

When you see a beachball cursor or the slowness is especially bad, note the exact time: hour, minute, second.  
These instructions must be carried out as an administrator. If you have only one user account, you are the administrator.
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 and start typing the name.
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.
Each message in the log begins with the date and time when it was entered. Scroll back to the time you noted above.
Select the messages entered from then until the end of the episode, or until they start to repeat, whichever comes first.
Copy the messages 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 it useless for 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.
When you post the log extract, you might see an error message on the web page: "You have included content in your post that is not permitted," or "The message contains invalid characters." That's a bug in the forum software. Please post the text on Pastebin, then post a link here to the page you created.