Go to: http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
In the 112 block, click on the accept radio button then click on: jdk-8u112-windows-i586.exe
Download and install it.
In your "Search Windows" box type "cmd". It should give you an option to run the "Command Prompt".
In the Window that opens type:
cd C:\"Program Files (x86)
This may give you an error if you've already created the directory. Next type in:
keytool.exe -genkey -v -keystore %HOMEPATH%\keystores\android.keystore -alias release -keyalg RSA -validity 999999
It's should start asking you a bunch of questions that you will have to provide answers that make sense for you. The sequence should go something like:
C:\Program Files (x86)\Java\jdk1.8.0_112\bin>keytool.exe -genkey -v -keystore %HOMEPATH%\keystores\android.keystore -alias release -keyalg RSA -validity 999999
Enter keystore password:
Re-enter new password:
What is your first and last name?
[Unknown]: Rob Miracle
What is the name of your organizational unit?
[Unknown]: Developer Relations
What is the name of your organization?
[Unknown]: Corona Labs
What is the name of your City or Locality?
What is the name of your State or Province?
What is the two-letter country code for this unit?
Is CN=Rob Miracle, OU=Developer Relations, O=Corona Labs, L=Austin, ST=TX, C=US correct?
Generating 2,048 bit RSA key pair and self-signed certificate (SHA256withRSA) with a validity of 999,999 days
for: CN=Rob Miracle, OU=Developer Relations, O=Corona Labs, L=Austin, ST=TX, C=US
Enter key password for <release>
(RETURN if same as keystore password):
C:\Program Files (x86)\Java\jdk1.8.0_112\bin>
Now this is as "Copy and Paste" as I can make this. Java may or may not install in the directory that it installed for me.
How you bring up the command prompt may be different.
You may choose to have a different password for the .keystore file and for the "release" keystore. In my example I chose to use the same password for both.
Your Keystore file will be in C:\Users\yourname\keystores\android.keystore and you can tell Corona to go to that folder and use the keystore you created.