string source = @"\abcC$tempcoll.zip";
string destination = @"\defc$tempcoll.zip";
string destDirectory = Path.GetDirectoryName(destination)
if (File.Exists(source) && Directory.Exists(destDirectory)) {
    File.Copy(source, destination);
}
else {
    // Throw error or alert
}

\MyComputerNameC$temptemp.zip