You want to do embed the file as a resource.
Right-click the project file, select Properties.
In the window that opens, go to the Resources tab, and if it has just a blue link in the middle of the tab-page, click it, to create a new resource.
In your code you can type in Resources.TheNameYouGaveTheFileHere and you can access its contents. Note that the first time you use the Resources class in a class, you need to add a using directive (hit Ctrl+. after typing Resources to get the menu to get VS to do it for you).
Do you need help with the saving of the file also?
Edit:
You could do something like this:
var resource = Properties.Resources.yourResource;
FileStream fileStream = new FileStream("filename.exe", FileMode.CreateNew);
for (int i = 0; i < resource.Length; i++)
fileStream.WriteByte((byte)resource[i]);
fileStream.Close();
Does it help you?
EDIT:
As I can see you are getting a stream, here is an update to make it work:
var resource = Properties.Resources.yourResource;
FileStream fileStream = new FileStream("filename.exe", FileMode.CreateNew);
resource.CopyTo(fileStream);
fileStream.Close();
Does it work now?