Im trying to find my grandad but wouldn't know where to start?

I want to find my bialogiacal grandad, the last time i saw him was when i was about 16 years ago... the only problem i've got is that i only know his name (Peter Clayton) and were he used to live, i dont know were to start at all. I've tried talking to my dad about him but he doesn't want to talk about his which is understadable due to the upsetting up bringing he had. The reason i want to find him is because i want to know that he is alright, also i have suffered from ill health for a while now and have been going to the hospital for alot of tests, if i was to kno were he is i could find more out about my family medical history. I've got alot of questions in my head that need to be answered and i need to know he's alright! can anyone help???