Every forum I've been to has been polite to those of us who have read the forum guidelines, have searched the topic before posting, and have provided as much info as possible. Here it seems like the thing is to lambast the noobs.
Well, first of all - which compiler do you want to use? MinGW/GCC?
Second: Where is it installed, what compiler pack (version...) did you choose?
Third: Are you sure you installed the compiler correctly? E.g. MinGW / GCC sometimes ships in two (or more) parts, splitting the C from the C++ compiler. So just installing the C compiler will obviously not be enough.
Finally: Do you point to the root directory of the compiler (as written on the compiler setup page), not any subfolder?
You can"debug" what you are doing at the command line: Try to compile a hello world app to see if the compiler itself is setup correctly.