here are two solutions,
both will work in window application but for web application use second solution.
1. set labels property 'UseMnemonic'='False'
label1.UseMnemonic=false;
label1.Text="This is the example & excercise";
2. Replace with '&' with '&&'.
label1.Text="This is the example & excercise".Replace("&","&&");
Happy Coding!
:)