C# Hangman Please Help with Bugs

I get an index out of range when I make a empty guess, I also have problem with updating my score label. Currently it will only increament if I guess the first letter. It won’t detect any other letters. I’d also like to make sure the user can’t keep entering a valid letter to get more points, please help just got back to learning c# and projects like this help me learn :slight_smile:
https://codepaste.net/1iacjb

If you can upload the whole project that would be easy for debug