Hawking's Doctor

Listen up, buttercup. This joke is playing on the fact that Stephen Hawking was a super smart dude famous for physics and also for using a computer to talk. So, instead of going to a regular doctor when he's sick, the joke asks if he'd go to Currys PC World, which is a place that sells computers and stuff. Get it? It's funny because it mixes his need for tech with a common question about health.