silent install of the VC 8.0 runtime (vcredist) packages

if you have downloaded the standalone VC 8.0 redistributable packages, you will need to modify the command lines slightly. The following command lines can be used to install the original release of the standalone VC 8.0 redistributable packages:

For x86: vcredist_x86.exe /q:a /c:"VCREDI~1.EXE /q:a /c:""msiexec /i vcredist.msi /qn"" "
For x64: vcredist_x64.exe /q:a /c:"VCREDI~2.EXE /q:a /c:""msiexec /i vcredist.msi /qn"" "
For ia64: vcredist_ia64.exe /q:a /c:"VCREDI~3.EXE /q:a /c:""msiexec /i vcredist.msi /qn"" "
The following command lines can be used to install the Visual Studio 2005 SP1 release of the standalone VC 8.0 redistributable packages:

For x86: vcredist_x86.exe /q:a /c:"VCREDI~3.EXE /q:a /c:""msiexec /i vcredist.msi /qn"" "
For x64: vcredist_x64.exe /q:a /c:"VCREDI~2.EXE /q:a /c:""msiexec /i vcredist.msi /qn"" "
For ia64: vcredist_ia64.exe /q:a /c:"VCREDI~1.EXE /q:a /c:""msiexec /i vcredist.msi /qn"" "
If you would like to install the VC runtime packages in unattended mode (which will show a small progress bar but not require any user interaction), you can change the /qn switch above to /qb. If you would like the progress bar to not show a cancel button, then you can change the /qn switch above to /qb!

Some folks ask me what vcredist.msi..
Iy means that you want to extract the embedded msi from the self exe package and be able to run msiexec which is used to install the package. msiexec is the Microsoft Installer runtime.
MSI is the prefered format for microsoft installer. Installshield and Visual Studio 2005 and higher can generate MSI. Using the msiexec command. You can even log all the installer session to a file and you can verify and explore the content of the MSI using ORCA in order to look at the installer sequence, string table and in some cases embedded Visual Basic Script. Yes Visual Basic is not dead. Still used and convnient enough for scripting installer code :)

If you want to install the runtime from a Null Soft Installer NSI script with minimal UI and progress bar, here is what you want to do

;extract selft exe to temp
SetOutPath "$TEMP"
; uncompress
File "${RUNTIME_VCREDIST}"



;-------------------------------
; Test if Visual Studio Redistributables 2005+ SP1 installed
; Returns -1 if there is no VC redistributables intstalled
Function CheckVCRedist
Push $R0
ClearErrors
ReadRegDword $R0 HKLM "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{7299052b-02a4-4627-81f2-1818da5d550d}" "Version"

; if VS 2005+ redist SP1 not installed, install it
IfErrors 0 VSRedistInstalled
StrCpy $R0 "-1"

VSRedistInstalled:
Exch $R0
FunctionEnd


Section "Installer Sections" SecDummy
SetOverwrite ifnewer
Call CheckVCRedist

;IntCmp $0 5 is5 lessthan5 morethan5
IntCmp $R0 -1 noVCRuntime noVCRuntime VCRuntime
;force install
; IntCmp $R0 -1 noVCRuntime noVCRuntime noVCRuntime

noVCRuntime:


;extract VCRuntime to Temp
SetOutPath "$TEMP"
File "${RUNTIME_VCREDIST}"

;/qn for complete silent install
;/qb small progress dialog but does not require any user interaction
;StrCpy $VC_RUNTIME "$\"$TEMP\vcredist_x86.exe$\" /q:a /c:$\"VCREDI~3.EXE /q:a /c:$\"$\"msiexec /i vcredist.msi /qb!$\""
StrCpy $VC_RUNTIME "$\"$TEMP\vcredist_x86.exe$\" /q:a"

;MessageBox MB_ICONINFORMATION 'Need to install VCRuntime {$R0} {$VC_RUNTIME}'

ExecWait '$VC_RUNTIME' $0
;MessageBox MB_ICONINFORMATION 'Return Code {$0}'
;IntCmp $0 0 done

;MessageBox MB_ICONINFORMATION 'install complete'

Delete "$TEMP\vcredist_x86.exe"

Goto VCRuntime

VCRuntime:

SectionEnd


http://blogs.msdn.com/astebner/archive/2007/02/07/update-regarding-silent-install-of-the-vc-8-0-runtime-vcredist-packages.aspx