Cygwin1.dll 'not found' when running a program written in C. How can I make Windows find it?

Question

So I\'m trying to run my first hello world prog written in C. I compiled it in eclipse and get no errors, but when I try to run it I get:

\"This application has fail

Answer 1

I had the same problem... Adam Rosenfield's answer solved it nice. At my Computer the path needs to be "C:\cygwin64\bin"

First time I didn't recognized that my version of cygwin is the 64bit... But it's quiet clear that these little difference in the path-variable decides if it will work - or not.