Keypad Scanner help!

YES YES YES ! with your previous code, you are right.

...
SIGNAL sig : std_ulogic_vector(3 downto 0) := "0000";
PROCESS (clk)
BEGIN
If rising_edge(clk) THEN
    sig <= "1010"; -- sig will be affected at the end on the process, so here at the first clk edge, 
    -- sig still equals to "0000" for this time !
    IF sig = "1010" then
        -- instructions here 
        -- that are NOT executed because sig = "0000"
        -- will be executed at the next clk edge
    ELSE
        -- instructions that will be executed the first time
    END IF;
END IF;
END PROCESS;