Mineral Oil doesn't conduct electricity, however it does heat up very quickly so you'd still have to cool the mineral oil with a radiator of some sort, if people were using the computer for anything like games or movie editing. It also corrodes if it isn't filtered. So there'd need to be a good filter of at least 10 microns. Even then you'd have to replace the oil every 3 months or so 'cause it'd discolor.