Environment Vaiables is present in the Software Environment category in the System Information. It displays  information about your computer environment, which are  the number of processors, the operating system path, and the location of temporary folders.

To get in to the Environmental Variables:-

Right click on My Computer>Select Properties>Click on the Advanced tab>Click on Environmental Variables present under Startup and Recovery.

Now click the name of the user variable or system variable you want to change, as follows.   Here you can :-

New to add a new variable name and value.

Edit to change a current variable name and value.

Delete to remove a variable name and value.

Remember if you are not logged on as administrator to the local computer, the only  you can change are user variables.