Flash player Not Available, multiple downloads

I've installed FlashPlayer many times, but my broser( Firefox or Waterfox) doesn't know it. "Install missing plugins" appears after installation. Please help with this very annoying problem.

System  

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  Manufacturer TOSHIBA

  Model Satellite L600

  Total amount of system memory 4.00 GB RAM

  System type 64-bit operating system

  Number of processor cores 2

Storage  

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  Total size of hard disk(s) 466 GB

  Disk partition (C:) 80 GB Free (206 GB Total)

  Disk partition (D:) 55 GB Free (164 GB Total)

  Disk partition (E:) 35 GB Free (95 GB Total)

  Media drive (F:) CD/DVD

  Media drive (K:) CD/DVD

Graphics  

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  Display adapter type AMD Radeon HD 6500M/5600/5700 Series

  Total available graphics memory 2746 MB

        Dedicated graphics memory 1024 MB

        Dedicated system memory 0 MB

        Shared system memory 1722 MB

  Display adapter driver version 8.980.0.0

  Primary monitor resolution 1366x768

  DirectX version DirectX 10

Network  

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  Network Adapter Atheros AR8152/8158 PCI-E Fast Ethernet Controller (NDIS 6.20)

  Network Adapter Realtek RTL8188CE Wireless LAN 802.11n PCI-E NIC

  Network Adapter TAP-Win32 Adapter V9