To help us furthur help you, please try these steps.
Reset PRAM by holding CMD, OPT, P, R at boot until you hear the Chime again.
Then login to an administrator account and try to create a new account.
If the issue does not present itself in the new account, that is great, if it does follow this step.
--> System Preferences ---> Keyboard ---> Keyboard Shotrcuts --> Click "Restore Defaults" then click back to "Keyboard" tab then hit "Input Sources". Please check ONLY the appropriate keyboard map. If your Mac was purchased in the US choose "US". Make sure it is just US and not US extended or such.
I also have this exact problem with my macbook pro early 2011 such that when I press:
2, it gives 2`
1 - - - > 1 and volume up
3 - - - > 3$
4 - - - > 4]
5 - - - > 5[
6 - - - > 6=
8 - - - > 8 and right
9 - - - > 9 and up
` - - - > 2`
= - - - > 6=
Right arrow - - - > 8
Up arrow - - - > 9
Only 7 works properly
It all started while using Windows 8.1 and it has also affected my Mac OSX Mavericks.
What should I do???