[Dev-C++] failure to execute

[Aimee S. <Ai...@ca...>]

Greetings;
   I was working with my students last night on Dev-C++.  We encountered a
few problems -- the most perplexing one being that when they altered the
code and then rebuilt the prog. then executed it, the previous program was
run and had not rebuilt/complied the altered code.  
If we copied and pasted the program into a new environment then it worked
just fine.  
This was not a consitent error, just an infrequent one but I wouldn't have
thought that it would have happened at all.  
Is there something that I can do to sort this out or did I not tell them
something that I needed to?
thanks,
aimee