There may be some incorrect language setting for the keyboard inputs.
Try set the character layout to English (British). Refer to the following.
1. Click Start, point to Settings and click Control Panel.
2. Double-click Keyboard icon and click Language tab.
3. Choose English (British) language and click OK.
If this doesn't solve the problem, there could be problems with the keyboard or hardware.
Please send the set in for our inspection.