I've not used Windows 7, only Vista and before.
On e.g. Vista, right click on 'My Computer' icon or go to the control panel and click on 'System'.
In the top left of the form under 'Tasks', click on 'Advanced System Settings'. This brings up a dialog entitled 'System Properties'. In the bottom right you'll find a button 'Environment Variables…'. Click on it.
This brings up a dialog 'Environment Variables'. You can add Glade env vars to the 'User Variables' section.
You don't need to set ANY env vars to use Glade, however to use the online documentation GLADE_HOME needs to be set to where you unzipped the files to, i.e. the directory path containing the 'html' subdirectory.
So if you installed Glade to e.g.
then set GLADE_HOME to the above path.
There are a few other potentially useful env vars:
GLADE_DRC_FILE – sets the default python drc file used when you use the command Verify->DRC->Run…
GLADE_EXT_FILE – the same, but for Verify->Extract->Run…
GLADE_USE_OPENGL – set to 'no' if you do not want to use OpenGL. Don't set this variable if you do want to use OpenGL.
GLADE_NO_EXCEPTION_HANDLER – disables the global exception handler. Sometimes useful when tracking down crashes, as the resulting crash dump may contain useful info.
Lastly you mention you didn't need to use the vcredist_x64.exe installer – this may not be required if your machine already has the Microsoft C++ runtime redistributables installed. See e.g. http://www.microsoft.com/downloads/en/details.aspx?familyid=ba9257ca-337f-4b40-8c14-157cfdffee4e&displaylang=en