Yep, you can install all the stuff right away. just do the registration to avail the warranty though.
That C drive has all the stuff already installed. You must be having a DVD which has some stuff but says all that is already installed on your laptop.
I recently bought an Inspiron... bargained for that studio 1558 in a shop in Singapore for 1150 singapore dollars which is bought at about 34 but then left it and when I came back it was gone. Damn, missed a great deal