Q:

OpenCV - DLL missing, but it's not?

I am trying just a basic program with OpenCV with the following code:
#include "cv.h"
#include "highgui.h"

int main()
{
    IplImage* newImg;
    newImg = cvLoadImage("~/apple.bmp", 1);
    cvNamedWindow("Window", 1);
    cvShowImage("Window", newImg);
    cvWaitKey(0);
    cvDestroyWindow("Window");
    cvReleaseImage(&newImg);
    return 0;
}

When I run this, I get 

The program can't start because
  libcxcore200.dll is missing from your
  computer.  Try reinstalling the
  program to fix this problem.

However, I can see this DLL.  It exists.  I have added the following to the input dependencies for my linker

C:\OpenCV2.0\lib\libcv200.dll.a
  C:\OpenCV2.0\lib\libcvaux200.dll.a
  C:\OpenCV2.0\lib\libcxcore200.dll.a
  C:\OpenCV2.0\lib\libhighgui200.dll.a

What gives? I'm using visual studio 2008.
When I link the .dll files instead of .dll.a files, I get 

fatal error LNK1107:invalid or corrupt
  file: cannot read at 0x3F8
  libcv200.dll

A:

I followed instructions on http://opencv.willowgarage.com/wiki/VisualC%2B%2B_VS2010 but was still stuck on exactly the same problem, so here's how I resolved it. 

Fetched MSVC 2010 express edition.
Fetched Win 32 OpenCV 2.2 binaries and installed in default location.
Created new project.
Project setup
Project -> OpenCV_Helloworld Properties...Configuration Properties -> VC++ Directories 
Include Directories... add: C:\OpenCV2.2\include\;
Library Directories... add: C:\OpenCV2.2\lib;C:\OpenCV2.2\bin;
Source Directories... add:
C:\OpenCV2.2\modules\calib3d\src;C:\OpenCV2.2\modules\contrib\src;C:\OpenCV2.2\modules\core\src;C:\OpenCV2.2\modules\features2d\src;C:\OpenCV2.2\modules\flann\src;C:\OpenCV2.2\modules\gpu\src;C:\OpenCV2.2\modules\gpu\src;C:\OpenCV2.2\modules\highgui\src;C:\OpenCV2.2\modules\imgproc\src;C:\OpenCV2.2\modules\legacy\src;C:\OpenCV2.2\modules\ml\src;C:\OpenCV2.2\modules\objdetect\src;C:\OpenCV2.2\modules\video\src;

Linker -> Input -> Additional Dependencies...
For Debug Builds... add: 
opencv_calib3d220d.lib;opencv_contrib220d.lib;opencv_core220d.lib;opencv_features2d220d.lib;opencv_ffmpeg220d.lib;opencv_flann220d.lib;opencv_gpu220d.lib;opencv_highgui220d.lib;opencv_imgproc220d.lib;opencv_legacy220d.lib;opencv_ml220d.lib;opencv_objdetect220d.lib;opencv_video220d.lib;

At this point I thought I was done, but ran into the problem you described when running the exe in debug mode. The final step is obvious once you see it, select:
Linker -> General ... Set 'Use Library Dependency Inputs' to 'Yes'
Hope this helps.

A:

Just add C:\OpenCV2.0\bin into your PATH environment variable 
or 
When  you install OpenCV, 
Choose the option, Add OpenCV to the system PATH for current user which is not default one

A:

Just for your information,after add the "PATH",for my win7  i need to reboot it to get it work.

