Take a look at the Win32::Process::List module, it's probably all you need. Alternatively, you could get away with a simple

 
my @proc_lines = `tasklist`;
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but then you would have to parse the lines for the relevant info yourself. Win32::Process::List does that already.

UPDATE: A small example from the module documentation:

use warnings;
use strict;
use Win32::Process::List;

my $plist = Win32::Process::List->new();
my $pid = $plist->GetProcessPid("explorer");
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