You could try the keyboard driver and see if that is it.
1. Delete the keyboard driver.
2. Reboot the computer (yes, before installing again).
3. The driver should automatically install when the computer and Windows restart.
Also, here are a few ways to try Numlock. I know you said you already tried it, but figured would add the info just in case.
It may be a "Numlock" problem. Here are three ways to try and unlock it.
A. You can try this shortcut, press (together) the Fn + Nmlk keys.
B. You can also try disabling it in the registry...
1. Press the Windows key + R to bring up the Run box.
2. Type "regedit" and press "Enter" to open the Windows "Registry Editor".
3. In the "Registry Editor", open the following registry key.
HKEY_USER\.Default\Control Panel\Keyboard\
4. In the keyboard folder, you should see a string value named “InitialKeyboardIndicators” with a value of 0, 1, or 2. You need to change the value to 1, and you’re done.
NOTE: The Values are as follows...
0 = Num Lock is turned OFF after the logon.
1 = Disable Num Lock.
2 = Numlock is turned ON after the logon.
C. Disable NumLock in the BIOS
You can also change how your computer handles the NumLock, when the computer first boots up, through the BIOS.
1. Turn on your computer, and as soon as you see the initial POST boot screen, press the designated key for entering the BIOS Setup.
2. Locate the the “NumLock State,” “NumLock Key“, “Boot Up NumLock Status” or a similar option
3. Change the value to Disabled or Off.
4. Save your changes and exit the BIOS.