1) Open up your "Microsoft Keyboard" properties (aka Intellipoint)
2) Select the macro key you want to assign it to, and hit Configure
3) Select the option "Start a program, Web page, or file" and hit next
4) Type this into the box: Rundll32.exe Powrprof.dll,SetSuspendState Sleep
Njoy !
source : http://www.tomshardware.co.uk/forum/5145-63-windows-sleep-macro
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