lost the keyboard keys suddenly

You aren't telling us much. It sounds like you might have a faulty keyboard or malware. Please fill out your system specs in your user control panel and tell us what antivirus/antimalware program you use.

I have no clue what you just said, at all. Other than I now know you have a Fujitsu. If English is not your first language, please tell me, as it might help me assist you better. Please tell me if you have any kind of antivirus software installed. If not, install malwarebytes anti-malware. After that has cleaned any viruses from your computer, you can install Microsoft Security Essentials, which will protect you from further infections.

By anti-malware, do you mean malwarebytes? Viruses are more than capable of slipping past one AV program. I have no clue about multilingual keyboard settings. If you are sure that malware is not the problem, then your built in keyboard has a hardware issue, and will need to be replaced. I recommend contacting Fujitsu about the issue. They may be willing to replace the keyboard for free or for a small fee.

There is no setting I know of that causes letter keys to create numbers instead. If you are using a translator software, maybe, but I highly doubt it. Malware and hardware problems are your best bets in this case by far.

z3r010 said:

If this is a laptop just look for and press the "fn" key.

Every laptop I've used required the fn key to be held down, instead of just pressed once. Although depending on your settings, this may work. It never hurts to try at any rate. Also, the key may be stuck. Pull the key off if necessary (without breaking anything) to make sure the button below is not being pressed.