There is a Search feature here...
...that by using keywords, will answer ones questions many times, with some reading, without having to wait for answers to likely/ probably already been asked many times basic care question(s).
When do you feed your corn??
And what?
And how much?
A live or dead?
Please help me?
By your questions you need to be reading several care sheets NOW, before its to late for your captive.

You sound like you want to do the right thing, but first you have to know what the right thing to do is.
http://www.kingsnake.com/rockymountain/RMHPages/RMHnewpage11.htm
http://www.cornsnake.net/new/care.php3
90% of health care problems in reptiles
are improper (husbandry) care related.
Also, if you would care to do a
www.google.com search for "Corn Snake Care" or some variation of that theme , many basic care "sheets" should pop up for you.
If you happen to see one that says they eat crickets, that ones just plain wrong regarding that aspect of there diet. They like mice, mice, and more mice basically.
Hatchling corn snakes begin eating pinky mice, and progress up to adult mice once they are mature. Mice bought frozen and completely thawed out as needed is the safest and most convenient way to go.
A good rule of thumb, if your new to all this, is to feed the snake a food item that is the same, or close to, the snake's diameter.
Feed an item that is too large, and the snake will often regurgitate it. Snakes will also regurgitate if they do not have a warm area or if they are handled too soon after they eat.
Corn snakes can be fed two times a week, but once is usually enough. Clean water should be available at all times, corn snakes drink often.
Anything you don't understand, please be sure to ask after doing some
"basic 101 " care sheet reading.
Specific questions will get you specific answers many times and broad general questions will get a broad general answer, if at all.
Cornsnakes will do well in almost any container, provided it is big enough. Baby cornsnakes will do well in a 5 or 10 gallon tank. Always MAKE SURE IT IS ESCAPE-PROOF!!!
There are five basic things a new cornsnake keeper needs in the Corns "house" ;
-A secure lid
-A hide box
-A clean water dish
-Bedding
-Stable temperature

So, did you get that Corn Snake some dinner?