If you can, an actual test (using real hardware/software) might be better.
Not IT as such but we've interviewed people to work in the lab and they could answer all the questions but a depressing number couldn't actually do basic lab tasks like operate a pipette properly or some were flumoxed by things like building a test-tube rack
(I wish I was joking). Knowledge without a bit of common sense and some practical skills isn't that helpful.Ask them to solve some simple problems that come up frequently - see if they can follow a set of instructions to reset a users password for example.
For hardware you could ask them to work out why no image is coming up on a display (having dislodged the either the display or power cable enough that it's the problem, or have the monitor switched off at the plug socket).
Pick a past support call and ask them what sort of things they'd do/ask to resolve it.
A quiz of the acronyms used might be helpful.