Cumplea~nos feliz!
An n with a ~ over it can't be written correctly on the computer.
It's a little complicated. If you're running windows, in a word processing program or IM program, here's what you do:
First you press CTRL (and shift, depending on the symbol) and then the key with the accent you wanna use.
Then press the letter you want the accent to go on.
This works for tildes, grave, acute, and circumflex accents, umlauts and cedillas.
So just type it in that way in one of those fields, and paste it on here.
It doesn't work under Firefox on Linux.
Open up a word processor and try it there...I probably didn't explain that very well...