title: Problem with .Net Framework 3.5 applications running in .Net Framework 4
body: <p>I have developed an application using VB 2008 Express and this application is targeting on .Net framework 3.5. I done several installation on various OS like windows vista, XP, 7, etc and it was working quite OK as long as I can install the .Net Framework 3.5 successfully. </p>
  
  <p>Here comes a problem, I came across a PC running windows vista and it is installed with .Net Framework 4 so I wasn't able to install my .Net Framework 3.5. My application was able to run smoothly and some error message pop up.</p>
  
  <p>Anyone can give me some suggestions? Can I still install .Net Framework 3.5 even though the PC as a higher version of .Net Framework like .Net 4.</p>
  
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  <p>By the way, I apologise for not mentioning the exact error message because the installation when the eeror occured wasn't done by me and the person doing it didn't take down the exact error message. This is my biggest problem here =(. I know I am unprofessional on this part sorry about that.  But he did mention that it got something to do with .Net 4 Framework or something related to it.</p>
  
  <p>He did tried installing the .Net framework 3.5 but it doesn't allow him to do so. Is it becasue it does not allow an older version to be installed? Or do I have to install .Net 3.5 first then .Net 4.0 in this order?</p>
  
  <p>Please advise me. Thanks</p>