Question on the pronunciation: does that "u" sound like the "yu" in English, or it is flat, without the slide, as in "compooter"?
The hint says 'computer' can be translated as singular and plural. So it depends on the context. «Ho un computer» is singular because of the un.
I assumed it was "computatore" or "computatrice" because "to compute" in Italian is "computare" and the original computers before they were machines were people (usually women) who performed calculations.