# To just run a program use system
system ("c:\\my.exe\n");

# To get the output of a program use back tics (use ` not ')
$output =`c:\my.exe`;

# You can also use open with a pipe 
open (PROGRAM,"|c:\\my.exe"); #to write to the program
open (PROGRAM,"c:\\my.exe|"); #to read from the program
open (PROGRAM,"|c:\\my.exe|"): # DOES NOT WORK!!!!!

# if you need to read and write from a program you will need to use ipc; open2, expect, Comm.pl can do that for you