asp webmatrix adding sql database error

[checoo]

i am using asp web matrix to build a e-commerce website,
i am trying to build a simple register and login page, when ever i try
to add a data base, in sql, it says acess is denied or sql doesn't
exixt,
i have installed, dot net frame work sdk, do i need anything else to
download,

morever i am trying to create a visual directory,
when ever i press f5 i two options
the second option is for creating a virtual drive but i am unable to
select it!!!

moreover i was trying to encrypt the password file how can i do that

please help me i am a new learner