You can spawn off another process using Win32::Process. Below is some code I used to open a file in Notepad from a Tk program. Win32::Process is documented pretty well and there are plenty of examples out there. As other monks have stated, I'd be very wary of using fork with Perl on Windows. I've experimented with fork some on Windows and it seems like if you created more than a couple processes, it would crash in various ways.
".")|| die "Couldn't open the file $file\n";