I've never used Win32::API, but I just took a quick glance at teh perldocs for the Import method, followed the link to Win32::API::Type and then read the part that says...

SUPPORTED TYPES
This module should recognize all the types defined in the Win32 Platform SDK header files. Please see the source for this module, in the __DATA__ section, for the full list.

...so i clicked the "Source" link, scrolled down, and saw that it listed "VOID" as a valid type.

Which makes me wonder if this would work...

Win32::API->Import( 'mbrola', 'VOID reset_MBR()' )
   || print STDERR "Failed Import:\n$^E\n";
[download]