ReadFile (win32 API) cannot read more than 64 MB

[serio]

Hi to all members.
I have a little "c" program to read bytes from a hard drive. It works perfectly fine as long as the "nNumberOfBytesToRead" parameter in the ReadFile function (win32 API) is less than 64 MB. Anything bigger than that, results in the ReadFile function returning 0 (zero) indicating a failure of that function.
Could anybody put some light on this.
Many thanks to all,
Serge Matovic.