Yosemite slow, spinning beach ball at every action

Question

Description du problème :
Yosemite worked well for a month or more, until yesterday. I used for the first time a flight simulator downloaded from appstore (for 30 minutes), i don't even know why i did that. After that mbp was really hot. At next start mbp was very slow showing spinningball beach ball at every action (typing, opening folders). I deleted the app, but no improvement was shown. after that i noted there was 10.10.2 upgrade (i had 10.10.1). no improvement. I thought i had to clean a little bit so i downloaded adwaremedic, which found an adware and eliminated it. still no improvement. I finally looked up on support.apple and found plenty of people with this problem and followed intructions: deleted all third party and cleaning programs (fan control and flip4mac wont disappear from system preferences, how to be sure if i uninstalled them right?). anyway still no improvement.
I followed thisguide (Guide: How to solve Yosemite memory leaks and CPU usage) but i'm not sure if i managed to reset smc, as my left **** key doesn't work (i used the right one). still no improvement.
I was thinking about using clamxav (I've read it's the less invasive) to scan the mbp, is it a good idea or not?
might dropbox be a problem (after quitting it, if i try to delete it, it says it's not possible because plugins are in use!)
should i reinstall yosemite? if yes, is it necessary to do a backup?
Please help me. thank you
EtreCheck version: 2.1.7 (114)
Report generated 30 gennaio 2015 10:24:09 CET
Télécharger EtreCheck à http://etresoft.com/etrecheck
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Informations matérielles : ℹ️
  MacBook Pro (13 pouces, mi-2012) (Caractéristiques techniques)
  MacBook Pro - modèle : MacBookPro9,2
  1 2.5 GHz Intel Core i5 CPU : 2-core
  4 GB RAM Extensible
  BANK 0/DIMM0
  2 GB DDR3 1600 MHz ok
  BANK 1/DIMM0
  2 GB DDR3 1600 MHz ok
  Bluetooth: Bon - Handoff/Airdrop2 disponible
  Wireless: en1: 802.11 a/b/g/n
  La santé de la batterie : Normal - Comptage de cycles 890
Informations vidéo : ℹ️
  Intel HD Graphics 4000
  Color LCD 1280 x 800
Logiciel du système : ℹ️
  OS X 10.10.2 (14C109) - Temps depuis le démarrage : 0:23:52
Informations des disques : ℹ️
  Samsung SSD 840 Series disk0 : (500.11 GB)
  EFI (disk0s1) <non monté> : 210 Mo
  Recovery HD (disk0s3) <non monté> [Restauration] : 650 Mo
  iRod SSD (disk1) / : 498.88 Go (154.97 Go libre)
  Core Storage: disk0s2 499.25 Go Online
  OPTIARC DVD RW AD-5970H 
Informations USB : ℹ️
  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
Informations Thunderbolt : ℹ️
  Apple Inc. thunderbolt_bus
Gatekeeper : ℹ️
  Mac App Store et développeurs identifiés
Agents de lancement : ℹ️
  [désengagé] com.adobe.AAM.Updater-1.0.plist [Aide]
  [engagé] com.oracle.java.Java-Updater.plist [Aide]
  [engagé] org.macosforge.xquartz.startx.plist [Aide]
Daemons de lancements : ℹ️
  [engagé] com.adobe.fpsaud.plist [Aide]
  [engagé] com.microsoft.office.licensing.helper.plist [Aide]
  [engagé] com.oracle.java.Helper-Tool.plist [Aide]
  [engagé] com.oracle.java.JavaUpdateHelper.plist [Aide]
  [engagé] com.skype.skypeinstaller.plist [Aide]
  [engagé] org.macosforge.xquartz.privileged_startx.plist [Aide]
Éléments Ouverture : ℹ️
  iTunesHelper Applicazione (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)
Plug-ins internets : ℹ️
  MeetingJoinPlugin : Version : Inconnu - SDK 10.6 [Aide]
  FlashPlayer-10.6 : Version : 16.0.0.296 - SDK 10.6 [Aide]
  Default Browser : Version : 600 - SDK 10.10
  AdobePDFViewerNPAPI : Version : 11.0.09 - SDK 10.6 [Aide]
  AdobePDFViewer : Version : 11.0.09 - SDK 10.6 [Aide]
  Flash Player : Version : 16.0.0.296 - SDK 10.6 [Aide]
  QuickTime Plugin : Version : 7.7.3
  SharePointBrowserPlugin : Version : 14.4.7 - SDK 10.6 [Aide]
  Silverlight : Version : 5.1.20913.0 - SDK 10.6 [Aide]
  DirectorShockwave : Version : 12.0.3r133 - SDK 10.6 [Aide]
  JavaAppletPlugin : Version : Java 8 Update 31 Vérifier la version
Panneaux de préférences tiers : ℹ️
  Fan Control [Aide]
  Flash Player [Aide]
  Flip4Mac WMV [Aide]
  Java [Aide]
Time Machine : ℹ️
  Time Machine n’est pas configuré !
L’utilisation du CPU par processus : ℹ️
  13% mds
  4% WindowServer
  1% fontd
  0% ocspd
  0% AppleSpell
L’utilisation de la RAM par processus : ℹ️
  571 Mo com.apple.SpeechRecognitionCore.speechrecognitiond
  77 Mo installd
  56 Mo WindowServer
  52 Mo Finder
  52 Mo mds_stores
Informations de la mémoire virtuelle : ℹ️
  80 Mo RAM Disponible
  1.54 Go RAM Active
  1.47 Go RAM Inactive
  692 Mo RAM Résidente
  2.16 Go Pages entrants
  422 Ko Sorties pages
Informations du diagnostic : ℹ️
  Jan 30, 2015, 10:01:49 AM Examen de soi - succès
  Jan 29, 2015, 02:45:34 PM /Library/Logs/DiagnosticReports/Messages_2015-01-29-144534_[expurgé].hang
  Jan 29, 2015, 02:34:07 PM /Library/Logs/DiagnosticReports/firefox_2015-01-29-143407_[expurgé].hang
  Jan 29, 2015, 02:09:44 PM /Users/[expurgé]/Library/Logs/DiagnosticReports/SMART Utility_2015-01-29-140944_[expurgé].crash
  Jan 28, 2015, 08:29:11 PM /Library/Logs/DiagnosticReports/firefox_2015-01-28-202911_[expurgé].hang
Jan 28, 2015, 08:28:25 PM /Users/[expurgé]/Library/Logs/DiagnosticReports/plugin-container_2015-01-28-202 825_[expurgé].crash
  Jan 27, 2015, 10:39:18 PM /Users/[expurgé]/Library/Logs/DiagnosticReports/Skype_2015-01-27-223918_[expurg é].crash
  Jan 27, 2015, 04:44:42 PM /Library/Logs/DiagnosticReports/firefox_2015-01-27-164442_[expurgé].hang
Jan 27, 2015, 03:41:23 PM /Library/Logs/DiagnosticReports/storeaccountd_2015-01-27-154123_[expurgé].cpu_r esource.diag [Détails]

Answer 1

When you see the beachball, 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.