On Windows is there a **light-weight** IDE that can be used both with C and Perl?

Zeus is a language neutral IDE that can be be configured for almost any programming langauge.

It has features like syntax highlighting, code folding, project/workspace management, class browsing, macro scripting, integrated version control, ftp editing etc.

_{(source: zeusedit.com)}

Have you looked at Padre, the Perl Application Development and Refactoring Environment?

It's still in development so you can help make it better.

SciTE would be worth a look.