No mailbox database in exchange 2007 when i try to create a new user mailbox?

Nebrom Asked: No mailbox database in exchange 2007 when i try to create a new user mailbox?

when i try to create user mailbox from exchange console, i want to select mailbox, unlucky, it is empty,
i have already users that can send and receive local emails with in my LAN.
but i could not create a new mailbox user becausewhen i reach on the select mailbox, it shows me empty. i just i have the default first storage groupstorage.
all the Microsoft exchange services are running(information store, system attendant.. just all services are running, and i restart them many times, no change)
how can i solve this problem?and my 2nd questions, i cannot create new storage group, the error message is "The parent object for <new storage group> could not be found. Please check that InformationStore exists." but the Information Store is runningand i restart it many times, but i couldn't create it, it gives me that error. any help is welcomed. thanks