When I type words different letters appear and also I have a problem with the scroll.. the phone also act so slow in everything I do with it. what am I gonna do?

Follow the below mentioned method, also see the advantages of T9 dictionary :
1.
Check your manual to learn more about text messaging
Check your cell phone's user manual to see if your cell phone has the T9 function. While most new phones contain this function, if you have an older phone, you'll want to check to be certain. Look under the Text Messaging section in the manual.
2.
Enable T9 for easy texting
Enable the T9 setting on your cell phone. Some phone require that you enable this function. Check under your cell phone's Options menu and also under the text messaging options. Depending on your cell phone, you may be able to set T9 as the default method of text input or you may have to toggle the text input functions to choose T9 for every text message. Generally, the toggle key will be your asterisk key. Again, check your cell phone's manual for more information.
3.
Choose your language and other preferences for T9 texting
Pick your T9 preferences. Your T9 function may allow you to set several preferences. The most typical preference is language, and you also may able to set whether you want your cell phone to use T9 for word completion only or to predict which word you will type next. You may also be able to set the "delay" - the amount of time before your T9 function changes the letters you are typing to what it thinks they should be. Again, try your Options or Preferences menus in the text messaging module of your cell phone or consult your cell phone's manual. You will want to try different set-ups to determine which works best for you and your style of text messaging.
4.
T9 gives you more then one way to select the right word for your text message
Type your text message, toggling for T9 if your phone requires it. Once the T9 function is enabled or toggled, simply type the word you want. Do not be concerned if the letters do not appear correctly when you first start typing the word - they will correct themselves when you finish typing the word, as long as you spell it correctly. Your phone may offer a drop-down menu with word suggestions as you type. If your word shows up, scroll down and select it if you wish or continue typing your word. If your phone does not offer a drop-down menu, and the word that you type is not the word that you wanted, press the Down arrow key on your cell phone and another word will show up. Keep pressing the Down arrow until your word shows up. When you have the word you want, use the space function to continue typing.
5.
Add your own text expressions to T9
Add your own words to the T9 function. The T9 function comes with an extensive dictionary, but you can add your own words or abbreviations, too. Again, you may have to dig around the Options or Preferences section in the text messaging module of your phone. Once you find it, simply type and add your own special words or expressions to have them at your fingertip when you text.
Use T9 to express yourself in your own unique way!

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You must disable your Predictive text option, T9® predictive text mode allows you to type words with only one keystroke per letter, and the phone interprets what word you want. For example, to type the, press 8, 4, 3. To enable/disable T9® predictive text mode, select Options. Scroll to and select Prediction on or off.

Turn off the UAC by completing the following steps:-

1. On the computer, open Control panal and select User accounts.
2. Click Add or remove user accounts.
3. Select the account to be changed, and then click Turn user account control on or off.
4. Check that the Use user account control (UAC) to help protect your computer option is not selected.
5. Click OK.

go to sattings then find language click on it predictive text off

Yes, this happens when you have a mouse connected to a laptop. I had the same problem .... was worried I had a serious problem. But when I disabled the touch pad, everything was fine!

yes,
most of the time when your phone starts getting slow it might be time for a software update. go get it checked out at your local service provider. have a nice day.

sounds like one of the keys is sticking. check this out. If not uninstall driver and reinstall by plugging in again.

You probably have the function scroll button on. See the blue numbers on the letters? press function scroll to take it off and see if that is your problem.

hit # to toggle through the different modes... however, if you get used to using the 'autosuggest', it'll make things faster, and as you use it, it'll start to learn what words you use more often. just hit the key for whatever letter you want, and then you can cycle through suggestions, probably with up and down on the dpad, or take the suggested word with right.  you don't hit multiple buttons to get the letter you want, you let it guess for you.  so, to get 'hello', you press 43556, instead of 4433555555666.