My Gateway Laptop computer types the wrong characters for instance I press the letter o and the number 6 comes up

It sounds like you have num-lock activated as the O would usually be 6 on the keypad if using numbers

Don't know on your model, but undo num-lock

3 possibilities:
1. The keyboard is bad. If in warranty, Gateway will send you a replacement keyboard.
2. The software may be set up for a different keyboard other than the standard "qwerty" style. Settings... Control Panel... Keyboard.
3. You can't type worth a flip!

Sometimes with these type of errors, you need a tech to re-program or update your drivers. That causes the keyboard to register 6 instead of L or 9 instead of F, and etc.