Hi Ramadulei,
Welcome to Dell community!
When you press the key combination “SHIFT + 2”, is any other special character displayed instead of “@”?
Also, does the number 2 key have a "@" symbol on it? Did you check if the issue occurs in Notepad?
We can try checking the Keyboard Layout settings. If your computer has Windows 8 installed, refer the following link to check the keyboard layout: http://bit.ly/OmJQ0g
Ensure that the keyboard layout is English (United States).
Please post the results.