Renault Clio 2002 radio and interior lights not working. Help?

Hi, my radio and interior lights arent working on my 2002 Clio. i had my friend take a look at the fuses and as he went to put a new one in the blown fuse, it blew it. he tried again, and it blew it again. so he tried a larger fuse which shouldnt have blown and guess what, it blew it. Please help, as we have no idea whats wrong or how to fix it?

Thank you.