Upgrade wanted but only to OS X 10.7 - macbook pro

Question

Hi all
I currently have OS X 10.6.8 on my macbook pro. My university library software I need to install requires 10.7 minimum.
Here lies my dilemma - I upgraded to Yosemite yesterday but it made my computer MUCH slower and it wouldn't let me download open source Office alternatives such as Open Office or Libreoffice as they are not Apple Store approved apps. I needed to do that, as my old version of Neooffice suddenly didn't work and you now have to pay £30 for the upgrade. So I used time machine to go back to my original 10.6.8 settings.
So, is there a way to upgrade to 10.7 (not Yosemite) or over so I can install my university library programme AND be able to download some open source Office alternative or keep my old Neooffice version working?
Is there an OS X you would advise me to upgrade to eg Lion, Mountain Lion, Mavericks etc that is preferred?
Any advice and step by step instructions much appreciated.
Thanks

Answer 1

It's likely your Yosemite installation was messed up by the prior system you had installed.
Try these in order testing your system after each to see if it's back to normal:
1. a. Resetting your Mac's PRAM and NVRAM
    b. Intel-based Macs: Resetting the System Management Controller (SMC)
2. Restart the computer in Safe Mode, then restart again, normally. If this doesn't help, then:
Boot to the Recovery HD: Restart the computer and after the chime press and hold down the COMMAND and R keys until the Utilities menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.
3. Repair the Hard Drive and Permissions: Upon startup select Disk Utility from the Utilities menu. Repair the Hard Drive and Permissions as follows.
When the recovery menu appears select Disk Utility. After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list.  In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive.  If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and return to the main menu. Select Restart from the Apple menu.
4. Reinstall Yosemite: Reboot from the Recovery HD. Select Reinstall OS X from the Utilities menu, and click on the Continue button.
Note: You will need an active Internet connection. I suggest using Ethernet if possible
            because it is three times faster than wireless.
5. Reinstall Yosemite from Scratch:
Be sure you backup your files to an external drive or second internal drive because the following procedure will remove everything from the hard drive.
How to Clean Install OS X Yosemite
Note: You will need an active Internet connection. I suggest using Ethernet if possible
            because it is three times faster than wireless.