Browser out of date and can't install Adobe Flash Player

Question

My browser is out of date according to everything I am visiting.  I can't post pictures on twitter, some of the videos I watch have blocked plug-ins, and I can't install adobe flash player.  My computer is a MacBook Pro 10.6.4, and I would like to keep Safari.  Can someone direct me to where I get the newest version of Safari and why I cannot install Adobe Flash Player.  I have installed, uninstalled, and done everything I know to do to get this problem resolved.  Next step is take it to the Apple store as I am not a tech person.  Thanks for any assistance.

Answer 1

Upgrade to Snow Leopard 10.6.8: Mac OS X 10.6.8 Update Combo v1.1. Upgrade further:
Upgrading to Yosemite
You can upgrade to Yosemite from Lion or directly from Snow Leopard. Yosemite can be downloaded from the Mac App Store for FREE.
Upgrading to Yosemite
To upgrade to Yosemite you must have Snow Leopard 10.6.8 or Lion installed. Download Yosemite from the App Store. Sign in using your Apple ID. Yosemite is free. The file is quite large, over 5 GBs, so allow some time to download. It would be preferable to use Ethernet because it is nearly four times faster than wireless.
    OS X Mavericks/Yosemite - System Requirements
      Macs that can be upgraded to OS X Yosemite
         1. iMac (Mid 2007 or newer) - Model Identifier 7,1 or later
         2. MacBook (Late 2008 Aluminum, or Early 2009 or newer) - Model Identifier 5,1 or later
         3. MacBook Pro (Mid/Late 2007 or newer) - Model Identifier 3,1 or later
         4. MacBook Air (Late 2008 or newer) - Model Identifier 2,1 or later
         5. Mac mini (Early 2009 or newer) - Model Identifier 3,1 or later
         6. Mac Pro (Early 2008 or newer) - Model Identifier 3,1 or later
         7. Xserve (Early 2009) - Model Identifier 3,1 or later
To find the model identifier open System Profiler in the Utilities folder. It's displayed in the panel on the right.
     Are my applications compatible?
         See App Compatibility Table - RoaringApps.
Upgrading to Lion
If your computer does not meet the requirements to install Mavericks, it may still meet the requirements to install Lion.
You can purchase Lion at the Online Apple Store. The cost is $19.99 (as it was before) plus tax.  It's a download. You will get an email containing a redemption code that you then use at the Mac App Store to download Lion. Save a copy of that installer to your Downloads folder because the installer deletes itself at the end of the installation.
     Lion System Requirements
       1. Mac computer with an Intel Core 2 Duo, Core i3, Core i5, Core i7,
           or Xeon processor
       2. 2GB of memory
       3. OS X v10.6.6 or later (v10.6.8 recommended)
       4. 7GB of available space
       5. Some features require an Apple ID; terms apply.