Mid-2012 MBP freezing, screen distortion & beeping, ahead of SSD upgrade - best course of action?

My mid-2012 MBP (10.8.5, Mountain Lion) has begun to freeze and screen-distort (blue horizontal lines) over the last few days. It has frozen twice, without screen distortion, when I have been moving the MBP between desks holding the left-hand side corner of the computer (i.e. where the battery/RAM is located), once when it was on my lap and I (stupidly) was tapping my foot on the ground (heard movement or clicking inside the computer before it crashed), and then once when the MBP was stationary on the desk, on top of a thick book.

The latter time is the only time the screen has distorted and the computer has frozen together. After this occasion (last night), I decided to remove the bottom and do some 'cleaning'. First, I took out the hard drive and reconnected it. When I turned it back on, the MBP booted in one of its 'beeping' modes, with a black screen and three equally-spaced beeps with a five second interval in between sets of beeps. I know this was, potentially, a RAM issue, so I removed, cleaned, and re-sat the RAM in the banks, and did the same with the hard drive again, just in case I had made a mistake previously with the HD. This worked and the MBP is running as normal now.

Next week, I had planned on upgrading the HD to a Crucial mx200 500gb SSD, as I found the MBP was becoming quite slow when running multiple applications and I could do with a quicker computer for running certain software, e.g. large simulations of statistical models in R.

Given the problems, and my plans for upgrades, what would be the best course of action? Should I upgrade the RAM too? In other words, it seems like the RAM may be causing the problem, and not the RAM banks. Or does it sound like the problem could be in the logic board or something more serious, and spending time to upgrade the RAM or SSD in this machine may be a waste of time until I get the real problem fixed?

I have pasted the Etrecheck for you all below.

Many thanks for your help and any tips of improving the clarity of my question and the information I have given is welcome.

EtreCheck version: 2.2 (132)

Report generated 7/26/15 10:24 AM

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Hardware Information: ℹ️

MacBook Pro (13-inch, Mid 2012) (Technical Specifications)

MacBook Pro - model: MacBookPro9,2

1 2.5 GHz Intel Core i5 CPU: 2-core

4 GB RAM

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 = 612 - SN = 9G223021ZD3MB

Video Information: ℹ️

Intel HD Graphics 4000 - VRAM: 512 MB

Color LCD 1280 x 800

System Software: ℹ️

OS X 10.8.5 (12F2518) - Time since boot: 1:18:42

Disk Information: ℹ️

APPLE HDD HTS547550A9E384 disk0 : (500.11 GB)

disk0s1 (disk0s1) <not mounted> : 210 MB

Macintosh HD (disk0s2) / : 499.25 GB (294.58 GB free)

Recovery HD (disk0s3) <not mounted> [Recovery]: 650 MB

HL-DT-ST DVDRW GS31N

USB Information: ℹ️

Apple Computer, Inc. IR Receiver

Apple Inc. BRCM20702 Hub

Apple Inc. Bluetooth USB Host Controller

Apple Inc. Apple Internal Keyboard / Trackpad

Apple Inc. FaceTime HD Camera (Built-in)

Thunderbolt Information: ℹ️

Apple Inc. thunderbolt_bus

Gatekeeper: ℹ️

Anywhere

Startup Items: ℹ️

HWNetMgr: Path: /Library/StartupItems/HWNetMgr

StartOuc: Path: /Library/StartupItems/StartOuc

Startup items are obsolete in OS X Yosemite

Launch Agents: ℹ️

[loaded] com.oracle.java.Java-Updater.plist [Click for support]

[running] HWPortCfg.plist [Click for support]

[loaded] org.macosforge.xquartz.startx.plist [Click for support]

Launch Daemons: ℹ️

[loaded] com.adobe.fpsaud.plist [Click for support]

[loaded] com.barebones.authd.plist [Click for support]

[loaded] com.DesignScience.DSMTTool.plist [Click for support]

[loaded] com.microsoft.office.licensing.helper.plist [Click for support]

[loaded] com.oracle.java.Helper-Tool.plist [Click for support]

[loaded] com.oracle.java.JavaUpdateHelper.plist [Click for support]

[loaded] com.tunnelbear.mac.tbeard.plist [Click for support]

[loaded] org.macosforge.xquartz.privileged_startx.plist [Click for support]

User Launch Agents: ℹ️

[loaded] com.adobe.ARM.[...].plist [Click for support]

[loaded] com.google.keystone.agent.plist [Click for support]

[failed] com.jdibackup.ZipCloud.autostart.plist [Click for support] [Click for details]

[failed] com.jdibackup.ZipCloud.notify.plist [Click for support] [Click for details]

User Login Items: ℹ️

iTunesHelper Application (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)

uTorrent Application (/Applications/uTorrent.app)

Dropbox Application (/Applications/Dropbox.app)

AdobeResourceSynchronizer Application Hidden (/Applications/Adobe Reader.app/Contents/Support/AdobeResourceSynchronizer.app)

CrossOver CD Helper Application (/Users/[redacted]/Applications/CrossOver.app/Contents/Resources/CrossOver CD Helper.app)

Internet Plug-ins: ℹ️

Flip4Mac WMV Plugin: Version: 2.4.4.2 [Click for support]

FlashPlayer-10.6: Version: 18.0.0.209 - SDK 10.6 [Click for support]

QuickTime Plugin: Version: 7.7.1

AdobePDFViewerNPAPI: Version: 11.0.11 - SDK 10.6 [Click for support]

Flash Player: Version: 18.0.0.209 - SDK 10.6 [Click for support]

AdobePDFViewer: Version: 11.0.11 - SDK 10.6 [Click for support]

SharePointBrowserPlugin: Version: 14.2.4 - SDK 10.6 [Click for support]

Silverlight: Version: 5.1.40416.0 - SDK 10.6 [Click for support]

JavaAppletPlugin: Version: Java 8 Update 51 Check version

User internet Plug-ins: ℹ️

Google Earth Web Plug-in: Version: 7.1 [Click for support]

Safari Extensions: ℹ️

MacCost

3rd Party Preference Panes: ℹ️

Flash Player [Click for support]

Flip4Mac WMV [Click for support]

Java [Click for support]

Time Machine: ℹ️

Time Machine not configured!

Top Processes by CPU: ℹ️

11% Google Chrome Helper(4)

6% Google Chrome

2% fontd

1% WindowServer

0% uTorrent

Top Processes by Memory: ℹ️

856 MB Google Chrome Helper(5)

164 MB Google Chrome

90 MB Dropbox

82 MB mds

45 MB mdworker(4)

Virtual Memory Information: ℹ️

835 MB Free RAM

3.18 GB Used RAM

0 B Swap Used

Diagnostics Information: ℹ️

Jul 26, 2015, 09:04:41 AM Self test - passed

Jul 25, 2015, 11:58:23 PM /Library/Logs/DiagnosticReports/Kernel_2015-07-25-235823_[redacted].panic [Click for details]