I see. You probably need to tinker with the Environment Variables to be able to use Java from the command line. I can show you how, but be very careful with it. You don't want to mess up your environment variables.
First, locate your Java install directory. You need the path to your java.exe executable.
It might look like this:
C:\Program Files (x86)\Java\jre7\bin
Once you have it, right click My Computer and select Properties. On the down right corner, there should be a "Change Settings" sorta button. You might need administrator access to click it. Under the "Advanced" tab, there should be an "Environment Variables" button down on the right side. Click that. The dialog that opens has the list of variables. You want to select the one named "Path". After clicking "Edit" you can input the Java directory, BUT do NOT replace what is already written there. Press the right arrow key to go to the very end, add a semi-colon (one of these ; ), and THEN paste in the Java directory you copied earlier.
Once that is done, just save the settings and try "java -version" in cmd to test if it works.
Again, I don't expect you to want to do this, so if you don't want to risk messing around with system settings, I can probably find someone who do. As I said, if you want to try it, be careful.