You could use the Tooltip class. To customize its appearance, you'll have to set OwnerDraw to true and IsBalloon to false. Then you would handle the Popup and Draw events. The Popup event gives you a chance to specify the bounds (size) of the Tooltip, and the Draw event supplies a Graphics object to specify how you want it rendered.
public partial class Form1 : Form
private void SetBalloonTip()
notifyIcon1.Icon = SystemIcons.Exclamation;
notifyIcon1.BalloonTipTitle = "NUST";
notifyIcon1.BalloonTipText = "Zvangu zvaita!!!!!... lol";
notifyIcon1.BalloonTipIcon = ToolTipIcon.infor;
notifyIcon1.Visible = true;
Create a project and add a notification icon.Copy and paste the above code and make some adjustments on the tittle,text,icon and the time you want it to be displayed depending on what you want to be displayed, run the program.The notification icon will pop out automatically.