Please how can I make codeblocks run on my system?

Hello,  I downloaded codeblocks 17.12 version last year in November and installed the GNC compiler and it was working fine. I wanted to start practicing all I had learned in my programming classes only for me to write the Hello World program and try to build and run it,  but it kept showing me the error message that the compiler could not be found. So I went to settings and reinstalled the compiler. Nothing happened. I uninstalled and reinstalled the program, but it still didn't work (this was like yesterday). I have an assignment to submit on Thursday and I really need the codeblocks to work. Please help.