Hi Jenifer,
What is the version of Bitdefender you are trying to install?
The reason why you are unable to install Microsoft Visual C++ 2010 on your windows 8 computer is that it is not compatible. Therefore I would suggest you to uninstall the Microsoft Visual C++ 2010 from your computer ad then install Microsoft Visual C++ 2013 on your computer.
Follow the steps given below.
Method 1: Uninstall the Microsoft Visual C++ 2010 from your computer.
Follow the steps when your computer has booted to desktop.
a) Press Windows + x key together and select Control Panel.
b) Click on Programs and Features.
c) Locate Microsoft Visual C++ 2010, right click and select Uninstall.
e) Follow the onscreen instructions to uninstall Microsoft Visual C++ 2010.
Method 2: Download Microsoft Visual C++ 2013 and install.
Click on the link given below and install in on your computer.
Visual C++ Redistributable Packages for Visual Studio 2013
http://www.microsoft.com/en-ca/download/details.aspx?id=40784
Install the Bit defender on your computer and check if it gets installed successfully. If it fails to install then try to install Visual C++ 2010 Redistributable Packages in compatibility mode. Follow the steps given in the link given below to install the Visual C++ 2010 Redistributable Packages in compatibility mode.
Make older programs compatible with this version of Windows
http://windows.microsoft.com/en-in/windows-8/older-programs-compatible-version-windows
Write to us with the status of the issue. We will assist you ahead.