What it is is a SEGA Naomi Cab. The base model NAOMI 26. They're quite common in the UK and Europe at the moment. Favorite use is in Motorway service stations and places like that.
It may well not have a PC in it.... The Naomi System is a development of an Extended JAMMA specification. The hardware in them is actually an extended version of the SEGA Dreamcast with extra memory and uses plug in cartridges.
Best Regards,
Julian (Fozzy The Bear)