I followed your recommendation and installed EtreCheck. Here is the report provided:
EtreCheck version: 3.1.5 (343)
Report generated 2017-01-30 17:04:36
Download EtreCheck from https://etrecheck.com
Runtime 8:11
Performance: Below Average
Click the [Support] links for help with non-Apple products.
Click the [Details] links for more information about that line.
Problem: Computer is too slow
Hardware Information:ⓘ
MacBook Pro (13-inch, Mid 2012)
[Technical Specifications] - [User Guide] - [Warranty & Service]
MacBook Pro - model: MacBookPro9,2
1 2.5 GHz Intel Core i5 (i5-3210M) CPU: 2-core
4 GB RAM Upgradeable - [Instructions]
BANK 0/DIMM0
2 GB DDR3 1600 MHz ok
BANK 1/DIMM0
2 GB DDR3 1600 MHz ok
Bluetooth: Good - Handoff/Airdrop2 supported
Wireless: en1: 802.11 a/b/g/n
Battery: Health = Normal - Cycle count = 313
Video Information:ⓘ
Intel HD Graphics 4000
Color LCD 1280 x 800
System Software:ⓘ
macOS Sierra 10.12.2 (16C67) - Time since boot: about 7 hours
Disk Information:ⓘ
APPLE HDD HTS547550A9E384 disk0 : (500.11 GB) (Rotational)
[Show SMART report]
EFI (disk0s1) <not mounted> : 210 MB
Recovery HD (disk0s3) <not mounted> [Recovery]: 650 MB
Macintosh HD (disk1) / [Startup]: 498.88 GB (189.00 GB free)
Encrypted AES-XTS Unlocked
Core Storage: disk0s2 499.25 GB Online
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
Western Digital My Passport 0837
Thunderbolt Information:ⓘ
Apple Inc. thunderbolt_bus
Gatekeeper:ⓘ
Mac App Store and identified developers
Kernel Extensions:ⓘ
/System/Library/Extensions
[not loaded] com.aliph.driver.jstub (1.1.2 - SDK 10.7 - 2017-01-23) [Support]
[not loaded] com.wdc.driver.1394HP (1.0.7 - 2017-01-23) [Support]
[not loaded] com.wdc.driver.1394_64HP (1.0.0 - SDK 10.6 - 2017-01-23) [Support]
[not loaded] com.wdc.driver.USBHP (1.0.5 - 2017-01-23) [Support]
[not loaded] com.wdc.driver.USB_64HP (1.0.0 - SDK 10.6 - 2017-01-23) [Support]
System Launch Agents:ⓘ
[not loaded] 7 Apple tasks
[loaded] 166 Apple tasks
[running] 71 Apple tasks
[killed] 36 Apple tasks
36 processes killed due to insufficient RAM
System Launch Daemons:ⓘ
[not loaded] 41 Apple tasks
[loaded] 163 Apple tasks
[running] 81 Apple tasks
[killed] 26 Apple tasks
26 processes killed due to insufficient RAM
Launch Agents:ⓘ
[failed] com.adobe.ARMDCHelper.cc24aef4a1b90ed56a725c38014c95072f92651fb65e1bf9c8e43c37a2 3d420d.plist (2017-01-19) [Support]
Launch Daemons:ⓘ
[loaded] com.adobe.ARMDC.Communicator.plist (2017-01-19) [Support]
[loaded] com.adobe.ARMDC.SMJobBlessHelper.plist (2017-01-19) [Support]
[failed] com.adobe.fpsaud.plist (2016-06-13) [Support]
[loaded] com.microsoft.office.licensing.helper.plist (2011-03-10) [Support]
User Launch Agents:ⓘ
[failed] com.adobe.ARM.[...].plist (2014-11-04) [Support] - /Applications/Adobe Reader.app/Contents/MacOS/Updater/Adobe Reader Updater Helper.app/Contents/MacOS/Adobe Reader Updater Helper: Executable not found!
[failed] com.apple.CSConfigDotMacCert-[...]@me.com-SharedServices.Agent.plist (2012-08-05) - /System/Library/Frameworks/CoreServices.framework/Frameworks/OSServices.framewo rk/Versions/A/Support/CSConfigDotMacCert: Executable not found!
[loaded] com.google.keystone.agent.plist (2017-01-13) [Support]
User Login Items:ⓘ
Garmin Express Service Application (2013-09-06)
(/Applications/Garmin Express.app/Contents/Library/LoginItems/Garmin Express Service.app)
iTunesHelper Application Hidden (2017-01-23)
(/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)
Dropbox Application
(/Applications/Dropbox.app)
Jawbone Updater Application
(/Applications/Jawbone Updater.app)
WDQuickView Application
(/Incompatible Software/WDQuickView.app)
Internet Plug-ins:ⓘ
AdobePDFViewerNPAPI: 15.023.20056 - SDK 10.11 (2017-01-28) [Support]
FlashPlayer-10.6: 22.0.0.192 - SDK 10.9 (2016-06-27) [Support]
QuickTime Plugin: 7.7.3 (2016-12-22)
AdobePDFViewer: 15.023.20056 - SDK 10.11 (2017-01-28) [Support]
Flash Player: 22.0.0.192 - SDK 10.9 (2016-06-27) Outdated! Update
SharePointBrowserPlugin: 14.7.1 - SDK 10.6 (2017-01-02) [Support]
3rd Party Preference Panes:ⓘ
Flash Player (2016-06-13) [Support]
WDQuickView (2012-10-09) [Support]
Time Machine:ⓘ
Skip System Files: NO
Auto backup: YES
Volumes being backed up:
Macintosh HD: Disk size: 498.88 GB Disk used: 309.88 GB
Destinations:
My Passport [Local]
Total size: 999.83 GB
Total number of backups: 60
Oldest backup: 12/26/15, 7:32 PM
Last backup: 1/30/17, 4:53 PM
Size of backup disk: Adequate
Backup size 999.83 GB > (Disk used 309.88 GB X 3)
Top Processes by CPU:ⓘ
14% com.apple.WebKit.WebContent(7)
7% com.apple.WebKit.Networking(2)
4% coreaudiod
4% kernel_task
3% nsurlstoraged(2)
Top Processes by Memory:ⓘ
950 MB com.apple.WebKit.WebContent(7)
628 MB kernel_task
98 MB mdworker(8)
94 MB Safari
70 MB Dropbox
Virtual Memory Information:ⓘ
642 MB Available RAM
16 MB Free RAM
3.37 GB Used RAM
627 MB Cached files
62 MB Swap Used
Diagnostics Information:ⓘ
Jan 30, 2017, 02:21:29 PM /Library/Logs/DiagnosticReports/com.apple.WebKit.WebContent_2017-01-30-142129_[ redacted].cpu_resource.diag [Details]
/System/Library/Frameworks/WebKit.framework/Versions/A/XPCServices/com.apple.We bKit.WebContent.xpc/Contents/MacOS/com.apple.WebKit.WebContent
Jan 30, 2017, 09:31:46 AM Self test - passed
Jan 29, 2017, 05:13:39 PM /Library/Logs/DiagnosticReports/firefox_2017-01-29-171339_[redacted].cpu_resour ce.diag [Details]
/Applications/Firefox.app/Contents/MacOS/firefox
Jan 29, 2017, 12:07:40 PM /Library/Logs/DiagnosticReports/iTunes_2017-01-29-120740_[redacted].cpu_resourc e.diag [Details]
/Applications/iTunes.app/Contents/MacOS/iTunes
Jan 28, 2017, 12:27:10 PM /Library/Logs/DiagnosticReports/suggestd_2017-01-28-122710_[redacted].cpu_resou rce.diag [Details]
/System/Library/PrivateFrameworks/CoreSuggestions.framework/Versions/A/Support/ suggestd