MBP mid-2012 Yosemite lag+beachball after every action (With EtreCheck report))

I just got my mid-2012 MBP back from Apple for repairs to its logic board and other stuff (it was having an issue the is widespread with in that and the previous model), but this has nothing to do with that. I recently got another MBP, and took its hard drive out and put it in this one(The mid 2012). Prior to moving it, I used the computer, which had 10.10.2 installed, and this problem occurred. After I move the HD I upgraded to 10.10.3.

Every time I:

open an application- Lag+beachball

open a folder- Lag+beachball

change between active applications- Lag+beachball

no reason at all- Lag+beachball

Get the idea?

I have tried resetting the SMC, PRAM, reinstalling yosemite, fixing permissions, following tips online on how to speed up yosemite, and spent hours on google and DuckDuckGo looking for answers. I have used an heavy OS on weak hardware before, but this is something wholly different, any help would be much appreciated!

EtreCheck version: 2.2 (132)

Report generated 5/23/15, 10:51 PM

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Click the [Click for details] links for more information about that line.

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

8 GB RAM Upgradeable

BANK 0/DIMM0

4 GB DDR3 1600 MHz ok

BANK 1/DIMM0

4 GB DDR3 1600 MHz ok

Bluetooth: Good - Handoff/Airdrop2 supported

Wireless: en1: 802.11 a/b/g/n

Battery: Health = Normal - Cycle count = 128 - SN = 9G4220DL5D3MB

Video Information: ℹ️

Intel HD Graphics 4000

Color LCD 1280 x 800

System Software: ℹ️

OS X 10.10.3 (14D136) - Time since boot: 10:54:9

Disk Information: ℹ️

TOSHIBA MK5065GSXF disk0 : (500.11 GB)

EFI (disk0s1) <not mounted> : 210 MB

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

Macintosh HD (disk1) / : 498.88 GB (457.38 GB free)

Core Storage: disk0s2 499.25 GB Online

HL-DT-ST DVDRW GS31N

USB Information: ℹ️

Apple Inc. FaceTime HD Camera (Built-in)

Apple Inc. BRCM20702 Hub

Apple Inc. Bluetooth USB Host Controller

Apple Inc. Apple Internal Keyboard / Trackpad

Apple Computer, Inc. IR Receiver

Thunderbolt Information: ℹ️

Apple Inc. thunderbolt_bus

Gatekeeper: ℹ️

Mac App Store and identified developers

Kernel Extensions: ℹ️

/Library/Application Support/Avast/components/fileshield/unsigned

[loaded] com.avast.AvastFileShield (2.1.0 - SDK 10.10) [Click for support]

/Library/Application Support/Avast/components/proxy/unsigned

[loaded] com.avast.PacketForwarder (2.0 - SDK 10.10) [Click for support]

Problem System Launch Agents: ℹ️

[failed] com.apple.mdworker.sizing.plist [Click for details]

Launch Agents: ℹ️

[running] com.avast.secureline.update-agent.plist [Click for support]

[loaded] com.avast.secureline.userinit.plist [Click for support]

[running] com.avast.update-agent.plist [Click for support]

[loaded] com.avast.userinit.plist [Click for support]

[not loaded] com.maintain.Restart.plist [Click for support]

[not loaded] com.maintain.ShutDown.plist [Click for support]

[running] com.maintain.SystemEvents.plist [Click for support]

Launch Daemons: ℹ️

[failed] com.apple.spirecorder.plist

[loaded] com.avast.init.plist [Click for support]

[loaded] com.avast.secureline.init.plist [Click for support]

[loaded] com.avast.secureline.uninstall.plist [Click for support]

[failed] com.avast.secureline.update.plist [Click for support]

[loaded] com.avast.uninstall.plist [Click for support]

[loaded] com.avast.update.plist [Click for support]

User Launch Agents: ℹ️

[loaded] com.avast.home.userinit.plist [Click for support]

[failed] com.avast.secureline.home.userinit.plist [Click for support]

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

[loaded] com.valvesoftware.steamclean.plist [Click for support]

User Login Items: ℹ️

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

Internet Plug-ins: ℹ️

Default Browser: Version: 600 - SDK 10.10

QuickTime Plugin: Version: 7.7.3

3rd Party Preference Panes: ℹ️

None

Time Machine: ℹ️

Time Machine not configured!

Top Processes by CPU: ℹ️

3% com.avast.daemon

0% Avast

0% mds_stores

0% WindowServer

0% cloudpaird

Top Processes by Memory: ℹ️

660 MB kernel_task

451 MB softwareupdated

229 MB mdworker(7)

188 MB com.avast.daemon

164 MB mds_stores

Virtual Memory Information: ℹ️

1.61 GB Free RAM

6.39 GB Used RAM

0 B Swap Used

Diagnostics Information: ℹ️

May 23, 2015, 11:43:46 AM Self test - passed

May 21, 2015, 12:58:25 AM /Library/Logs/DiagnosticReports/Cocktail_2015-05-21-005825_[redacted].hang

NOTE: I have noticed up to 5 different instances of the mdworker process and up to 2 different instances of node-webkit Helper showing up in Activity Monitor