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...