How to fix? Wordpress wp-markdown plugin corrupted syntax-highlighter-evolved plugin posts?

Help! I have been documenting some C++ code over the past few months on wordpress, with the Syntax-highlighter-evolved plugin. Everything had worked fine. e.g. the C++ codes displayed correctly in post. e.g. the following syntax will display C++ codes nicely in wordpress.

[code language="cpp"]
   c++ codes goes here...
[/code]

Recently, I have started exploring using mark-down in wordpress and started writing mark-down in new posts with the wp-markdown plugin.

... And then ... I realized all of my older posts (with codes wraped in the Syntax-highligher-evolved syntax) have all got corrupted!

For example, characters (like < > etc), got converted into HTML entities (like < > etc). In addition, I also see LOADS of HTML tags being inserted into the C++ codes.

See here for a sample post on my wordpress site. It contains some supposingly C++ codes which now looks nothing like C++ codes.

Following discovering this error I have attempted playing around with activating and deactiving the plugins to see if I could get back to the working state (i.e. codes being displayed as C++ codes, instead of hybrid C++/HTML code). No luck so far.

(Currently I have both syntax-highlighter-evoled and wp-markdown plugins activated).

Has anyone encountered similar problems before and how did you resolve this?

Would be very grateful for all the help!