Checking for vowels rewrite
You should adhere to the following:


Capitalize method names.
You don't need count variable.
Don't specify a return type, then not utilize it.


Point (1) and (3) could be rectified:

protected static void WriteToConsole(string input)
{
     Console.ForegroundColor = ConsoleColor.Cyan;
     Console.WriteLine(input);
}


The application code could then be:

var vowels = Console.ReadLine().Where(c =&gt; "aeiouAEIOU".Contains(c));

if(vowels.Any())
{
     foreach(var vowel in vowels.Distinct())
         WriteToConsole(String.Format("Your sentence contains the following vowel {0}", vowel);

    WriteToConsole(String.Format("Your sentence contains {0} vowels", vowels.Count());
}
else
{
     WriteToConsole("Your sentence doesn't have any vowels.");
}


Also to point out, in the other question to avoid duplicate entries an uneeded iterations of repeated vowels, I called .Distinct.  This alleviated that, but that would throw off your official count of how many vowels exist within the sentence.  So I call Distinct on the loop rather than the initial input.  

Also to avoid an unneeded count variable, I call .Count() on the IEnumerable, the feature exist so why not use it?