Cyclone-V SOC development kit not working properly

First is the board powered on?.. (I know but I have to ask)

Second, check the clock and data pins of the jtag header with a logic analizer or oscope to make sure they are toggling.

If you are getting data on both the TDO and TDI pins, look at the CLK pin closer. Try adding a 10-30 ohm resistor in series to better match the line impedence, because it may be you are getting reflections causing the jtag to be double clocked.

If you are not getting anything, start checking all the power supplies on the board, to make sure all of them are up and at their nominal voltage.

Hope this helps.