Click on 'Start', 'Control Panel' and then 'Printers and other Hardware'. Click on 'Keyboard'. A window will appear with controls to your keyboard. You can alter the repeat rate and the repeat rate. When you adjust the repeat rate, you can test it out in the box below to see whether it is right for you or not.
You can also alter the speed or your cursor and make other adjustments. If your keyboard still continues to repeat letters after you have adjusted it, then there could be a fault, particularly if it is second hand. You could always take your computer down to the store where you purchased it from and get them to have a look at it, although it may cost you to have it fixed if it is outside its guarantee period, so the best option would be to replace the faulty keyboard with a new one.
You can also alter the speed or your cursor and make other adjustments. If your keyboard still continues to repeat letters after you have adjusted it, then there could be a fault, particularly if it is second hand. You could always take your computer down to the store where you purchased it from and get them to have a look at it, although it may cost you to have it fixed if it is outside its guarantee period, so the best option would be to replace the faulty keyboard with a new one.