Most DMMs don't test capacitance. You can by a capacitance meter for who knows how much and you will have to remove the cap from the board to test it but capacitors are so cheap that if you did that you may as well replace it. Your problem could be C4, C5, Bridge rectifier BR2 and maybe but not likely the LM232 regulator at Q1. If you have the board out I would start by looking at the tracks on the front and back to see any signs of poor previous work or bad solder joints. You could use your DMM to test the resistance between the components. Check out this site for some good information.
http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Game_resets Go down to 4.8 game resets.
