Application showing an exception"file not found " - winforms

Question

I created an application in VS2010 with operating system WINDOWS XP.
Now, I updated the os to WIN 7 and also updated the location of the application.
So, while running the application for opening a file using open dialog box it showing some exception like"File Not Found".
It was working fine with WIN XP, but now it showing this error, if we keep that perticular file in bin folder its working fine , but if we choose a file from other drive or a folder it showing error.
enter code here
string chosen_file = "";
ofd.Title = "Open a file";
ofd.FileName = "";
ofd.Filter = "Text Files(*.txt)|*.txt|Rich Text Box(*.rtb)|*.rtb|Word Document(*.doc)|*.doc|HTML Pages(*.htm)|*.html|Cascading Style Sheet(*.css)|*.css|JAVA(*.java)|*.java|video file(*.wmv)|*.wmv|All Files(*.*)|*.*";
if (ofd.ShowDialog() == DialogResult.OK)
{
chosen_file = ofd.FileName;
// richTextBox2.LoadFile(chosen_file, RichTextBoxStreamType.PlainText);
var fileInfo = new FileInfo(ofd.FileName);
fileInfo.Length.ToString();
byte[] buffer = new byte[fileInfo.Length];
int length = (int)fileInfo.Length;
FileStream fileStream = new FileStream(fileInfo.Name, FileMode.Open, FileAccess.Read);
fileStream.Read(buffer, 0, length);}

Answer 1

My guess is you referenced a hard-coded path, probably to your "Documents" folder, rather than using an environment variable. With the change from XP to 7, that directory changed. I can't recall what the directory was for Windows XP, but it's now /users/username for Windows 7. Either way, you would be better off using an environment variable.
Look through your program for Documents and Settings and see if you can find it. If you go to a command prompt and type set, it should give you a list of environment variables you could use in place of whatever you were using.