I have thoroughly searched the entire access denied questions and did\'t find any question related to access to windows form on my own system all the questions are related t
"C:\\Users\\username\\Desktop"
is a directory for me; not a file.
Since you're attempting to open the file, this:
fsrw = new FileStream("C:\\Users\\Sainath\\Desktop", FileMode.Open, FileAccess.ReadWrite);
... should be
var fullpath = Path.Combine("C:\\Users\\Sainath\\Desktop", fname);
fsrw = new FileStream(fullpath, FileMode.Open, FileAccess.ReadWrite);