Where can I find bios.h and other headers?

You don´t mention which compiler you use, but look in your compilers include dir, in Visual C i didn´t find anyfile named bios.h but in djgpp it was in the include dir...
If you don´t find it search your harddrive for bios.h

If your compiler is windows-only (like MSVC 6.0), then you won''t find any bios.h because you don''t have access to the bios under windows.

Under DOS, it is in the include-directory, but this depends on the compiler!

Coder1000