My keyboard works partially, some letters dont work, some show the wrong ones

Hi,

1. Did you make any changes on the computer prior to the issue?
2. What is the make and model of the keyboard?
3. Are you using a desktop or laptop?
4. How is the keyboard connected (eg: ps2, usb,  wireless)?

Method 1:
You may perform a hardware troubleshoot and check:
Open the Hardware and Devices troubleshooter
http://windows.microsoft.com/en-us/windows7/Open-the-Hardware-and-Devices-troubleshooter

Method 2:
You may also try these suggestion provided and check:
•Make sure your keyboard is plugged in to your computer correctly. If the keyboard connects to a USB port, try unplugging the keyboard and plugging it into a different USB port.
•Many wireless keyboards require special drivers to work properly. Be sure that you have installed any software that came with the keyboard. If you use a wireless Bluetooth enabled device for your keyboard.

•Try plugging your keyboard into another computer. If it still doesn't work, it might be broken. Consider replacing it with a new keyboard, or, if the warranty for the keyboard is still valid, exchanging it for a new one with the manufacturer.

Method 3:
You may make sure that you have update the latest drivers from the manufacturer website.
http://windows.microsoft.com/en-us/windows7/Update-a-driver-for-hardware-that-isnt-working-properly

Method 4:
You may also turn the keyboard upside down and gently shake it. This will help remove any accumulated debris that might be preventing the keys from functioning properly. You might also want to use compressed air to clean out dust from hard-to-reach areas under the keys.

Method 5:
Your keyboard layout might be set for a different language than the one you want to use. See
http://windows.microsoft.com/en-US/windows7/Change-your-keyboard-layout
for instructions on changing the keyboard layout to match the language that you want to use.If this doesn't fix the problem; try plugging your keyboard into another computer. If it still doesn't work, it might be broken and need to be replaced.

Method 6:
You might have activated the Sticky Keys accessibility feature. To learn how to disable Sticky Keys, see: http://windows.microsoft.com/en-US/windows7/Make-the-keyboard-easier-to-use

You may also try to check if the keyboard is working fine on a different computer.

If you are using Microsoft product then you may refer the knowledge base articles for help:
Troubleshoot wired keyboards that don't respond or that type wrong characters
http://support.microsoft.com/kb/258826

Troubleshoot response failures in wireless keyboard or mouse

http://support.microsoft.com/kb/838398

My keyboard works partially, some letters dont work, some show the wrong ones.help!

Desktop or laptop computer?

(If you are getting numbers when expecting letters and this is a laptop...  Turn off numlock.)

Other keyboards work when attached?

(If yes to that last one - replace the defective keyboard.)