I have an HP DV9000 with Windows 7 Ultimate, which I updated recently with KB980408, KB975496, and KB972696. I figured at first that the reason for not being able to go into sleep mode was due to the updates at first however my laptop i still having issues with sleep mode. I tried editing the sleep mode configuration to allow and deny hybrid sleep as well as disable timers with mixed results. Generally when I attempt sleep mode the laptop screen goes black, the lights on the panel go dark but only for a second and then power back on. When I used the command powercfg -lastwake I got a response of
Wake History Count - 1
Wake History 
Wake Source Count - 0
Right before posting this issue my laptop had in fact powered into sleep mode for about 5 minutes and the powered back on so I am confused why the history doesn't show any activity. For the life of the laptop and while having Windows 7 I have not had this issue until this week. Anyone have any suggestions for me to try?