title: compilation error - Must define a target architecture
body: <p>I have a project that worked with windows vista and now I'm trying to compile the project on win 7. I'm getting compilation error :  Must define a target architecture.</p>
  
  <p>I looked for this error and I found that I need to change the "Compile for Architecture" in advanced  Project Properties. 
  The problem is that I can't find this option. I'm working with visual studio 2008. </p>
  
  <p>How can I solve this problem?</p>