woa, hold up... you can't expect a reply within minutes of postnig you know!!!
Anyway...
C# is a web scripting language, it's use for making pages active, it run on a webserver using the dotNET framework to do all kinds of clever stuff, For instance forums can be made in C# as well as quizzes, questionairres, hit couters, mail scripts and a whole host of other goodies...
COBOL is a (somewhat depreciated) programming language, it was invented way back when a computer room was a room that housed a single computer!!! it's made for making aplications, that actually run on a PC, Cobal was mainly used for making business aplpications, I'm told there is still a huge Cobal programming community, and tht Colbol programmers are still massivly sought after, but I'm yet to actally meet a Cobal rogrammer