Ungrounded Desktop PC; Workaround to Remove Static Charge?
You might be able to make your own ground wire, provided you're near a window and on the first floor. 

You'll need


A metal rod of some sort. Rebar might be commonly available. Doesn't have to be crazy long for these purposes, just has to stay in the ground
A clamp that fits around the metal rod
Some wire. Doesn't have to be a high gauge wire (18 gauge or so should work). If it's thicker than 16 gauge, make sure it's stranded and not solid.


Drive the rod into the ground by the window and fish some wire from inside to the rod and clamp it to that. Once that's done, take the other end and attach it to the case via a case screw (if you're using 18 gauge, just wrap the wire around a screw and re-tighten)

That should ground your computer (all computers ground to the case). All ground really is is an alternate path for excess electricity to flow to. That should alleviate the shocking problem you have. A GFI won't solve the problem because it's designed to detect an imbalance between the hot and neutral. It won't stop static buildup.