Gpedit or group policy editor, is tool provided by windows 7 ultimate and professional edition, and also windows 8. to configure your working environment in windows. the ability to edit some feature such as login, desktop setting, that is not provided with usual icon in windows, we can edit here. you can read the rest of article here http://en.wikipedia.org/wiki/Group_Policy

however other versions of windows 7 do not enable their gpedit, so you have to manually enable it, i found gpedit installer here http://www.askvg.com/how-to-enable-group-policy-editor-gpedit-msc-in-windows-7-home-premium-home-basic-and-starter-editions/

by using gpedit, you can use alternative version of regedit to change your windows environtment such as :
enable swiching user
disable aero shake
edit logon windows
remove task manager on Ctrl+alt+del
remove small icon like battery meter, internet explorer, dll
options in network connection
etc, you should browse it yourself and try it

you can run it by write gpedit.msc in
start > search program and files form