Macbook Pro running slow

Last week I updated my macbook pro 9,2 to the latest version of yosemite (I had time vault activated), first it took 3 hours to complete the update and after it finished, my computer became so slow and I were not able to use it. I decided to make a backup of my files which took 56 hours to complete (it was really slow), after that, I used the recovery mode to erase the disk and make a clean installation of Lion (It took about 3 hours to download and about 8 to install). This morning when the installation was completed, I started using Lion and the problem is still present!! I tried to install the office suite but every time the installer opens, it freezes!. I don't know what to do, its freaking me out. I'm a college student and I need to work on my computer every day!. Please help!

This person has the same issue: https://discussions.apple.com/thread/6823076

EtreCheck version: 2.1.8 (121)

Report generated February 9, 2015 7:46:27 PM CST

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Hardware Information: ℹ️

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

MacBook Pro - model: MacBookPro9,2

1 2.9 GHz Intel Core i7 CPU: 2-core

8 GB RAM

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 637

Video Information: ℹ️

Intel HD Graphics 4000 - VRAM: 512 MB

Color LCD 1280 x 800

System Software: ℹ️

Mac OS X 10.7.5 (11G63) - Time since boot: 1:50:28

Disk Information: ℹ️

TOSHIBA MK7559GSXF disk0 : (750.16 GB)

disk0s1 (disk0s1) <not mounted> : 210 MB

Macintosh HD (disk0s2) / : 749.30 GB (727.26 GB free)

Recovery HD (disk0s4) <not mounted> [Recovery]: 650 MB

MATSHITADVD-R UJ-8A8

USB Information: ℹ️

Apple Inc. FaceTime HD Camera (Built-in)

Apple Computer, Inc. IR Receiver

Apple Inc. BRCM20702 Hub

Apple Inc. Bluetooth USB Host Controller

Apple Inc. Apple Internal Keyboard / Trackpad

Microsoft Microsoft® Nano Transceiver v1.0

Thunderbolt Information: ℹ️

Apple, Inc. MacBook Pro

User Login Items: ℹ️

None

Internet Plug-ins: ℹ️

QuickTime Plugin: Version: 7.7.1

JavaAppletPlugin: Version: 14.3.0 - SDK 10.7 Check version

3rd Party Preference Panes: ℹ️

None

Time Machine: ℹ️

Time Machine not configured!

Top Processes by CPU: ℹ️

5% WindowServer

4% WebProcess

3% Safari

3% SystemUIServer

1% mds

Top Processes by Memory: ℹ️

344 MB WebProcess

283 MB Safari

60 MB mds

52 MB WindowServer

43 MB Finder

Virtual Memory Information: ℹ️

4.71 GB Free RAM

1.32 GB Active RAM

1.60 GB Inactive RAM

959 MB Wired RAM

2.62 GB Page-ins

0 B Page-outs

Diagnostics Information: ℹ️

Feb 9, 2015, 05:51:35 PM Self test - passed

Feb 9, 2015, 12:05:33 PM /Library/Logs/CrashReporter/spindump_2015-02-09-120533_[redacted].crash

Feb 9, 2015, 12:05:33 PM /Library/Logs/DiagnosticReports/spindump_2015-02-09-120533_[redacted].crash