When downgrading from Win 8 to Win 7 should I keep any of the partitions?

[mirileh]

I started the process of downgrading a T440S from Windows 8 to 7, and got stumped (and cold feet) on the partition choosing stage. Here is a photo of the partitions that are listed. Is there any reason not to delete them all? Is there any one I SHOULDN'T delete?

http://i.imgur.com/ywe9nVI.jpg

(After googling, I see this is the stage quite a few people messed up. Would LOVE a step by step guide for this one. Does one exist?)