A couple minor points (and maybe I'm a bit too new to PM to make the comments):

1. You probably should have this in a new question, not a reply on the previous question, since it's now a new question.
2. You probably should try something yourself, and then come back if it doesn't work. Or even if it does - share your answer and get feedback on it.

One WTDI is to use a simplified state machine:

my $match;
while (<FH>)
{
  print C $_ if $match and /^abcde.*PARTNAME$/;
  $match = /xyzdf$/;
}
[download]

This will set $match to true if the current line matches xyzdf at the end, false otherwise. The next time through the loop, we only check your second-line regexp if $match is already true (that is, the previous line matched the other regexp).