A reboot upon static discharge should not happen if the system is properly grounded.
Your power cord should have a three-prong plug, you should not be using a "cheater" plug to adapt it to a two-prong outlet, and the ground connection on the outlet should go to earth ground.
You can buy a $10 tester at Home Depot or Lowe's to test the outlet.
Also, do not use insulating washers with your motherboard mounting screws. They're supposed to ground the mobo to the chassis at all of the mount points. And do use as many as the mobo has mounting holes.
A PC case that has superfluous metal pieces, not electrically connected to the grounded part of the case, will be a problem here. All metal pieces (even painted ones) should be connected to the main case.