Details about environment variables in windows

We do not have oratab file in windows. Go to start->run->type "regedit". The registry will be displayed. Expand the folder called [HKEY_LOCAL_MACHINE]\SOFTWARE\ORACLE. Click on "KEY_*********", in the right hand side, we can find the details about environment variables. Another way to find out is, in the command prompt, type "set". The environment file will be displayed.