The wavy or squiggly dash that appears above the letter "N" is known as a tilde. It's a Spanish accent mark. Such a mark also appears on the letter "A." Keyboards in the United States usually don't have a specific button for the "N" with the tilde, so you'll need to use Windows keyboard shortcut symbols to type the letter. You can make either an uppercase "N" or lowercase "n."
Using a Desktop Computer
Open your word processing program. Push the "Num Lock" button on the upper-right side of your keyboard to turn the feature on. You should see a small light appear above the key, which tells you it's activated.
Press and hold the "Alt" button on the keyboard. There are two "Alt" buttons; you can push and hold either of them.
Tap the following numbers in succession: 164. Use the number pad, rather than the number keys on the top side of the keyboard. You should see a lowercase "n" with the Spanish accent mark.
Tap the following numbers in succession: 165. This types the uppercase "N" with the Spanish accent mark.
Using a Laptop Computer
Open your word processing program. Click on the Windows 7 start button.
Click on "Programs" then "Accessories." Click on the "System Tools" folder.
Click on "Character Map." You'll see a number of special characters inside the dialog box.
Browse through the list to find either the lowercase "n" with a tilde over it, or the uppercase "N." Click on it, and then click "Select."
Click "Copy." Switch back to your word processor. Click your right mouse button and select "Paste."