Visual Studio requires that minimum supported Windows Service Pack is installed on your computer before you install Visual ...

Visual Studio requires that minimum supported Windows Service Pack is 
installed on your computer before you install Visual Studio.  You can 
download and install Windows service pack from http://windowsupdate.microsoft.com..  After you install the service pack, you 
are required to restart your computer.  Visual Studio setup will not 
automatically restart.  To restart Visual Studio setup, double-click setup.exe 
from the original installation media or click the appropriate link on the 
download Web site.