deionized (pure) water is not electrically conductive because there are no ions present for the current to flow to.
From:
General Chemistry, Fith Edition, Ebbing 1996
Thom, you should be able to figure this one out, because if you dissolve NaCl into the pure water it becomes conductive, because the resulting ionic solution is really Na+, Cl-, and H2O. I'll let it slide this time because I had to look it up too

, and I'm taking P-chem now.
I'm pretty sure both of these coolants are too cold to allow your computer to operate. Hydrogen in liquid is -260C and Nitrogen is -210C.