Memory stick psp not recognising a brand new sony memory stick pro duo. i have tried cleaning the connections and also tried formatting the card in the psp, all it says is, no memory stick inserted. thanks

I had this very same problem with my unit when I first got it too. And I just went out and purchased a brand new memory stick duo and put it in, and for some reason, wallah! It was working like it never had a problem before! But you should clean all the contacts, blow inside the magic gate and make sure there is no debris/etc. inside there. Also, like the guy before me said, try upgrading the version of your software....

It might be that you need to upgrade your PSP.