hello every one;
i am very new to C
i have some experience in VB6

to be able to start from C kindly advise some doubts please
(1) is C is case sensitive
(2) is C is having a IDE like VB6
(3) is i must start from C so as to learn C++
(4) kindly advise some best & free IDE & Compilers for C please
(5) is C programes having user interfaces like , forms & GUI
(6) is it can be used for data base programming

please have patience for stupids