Windows Update KB2641653 prevents sleep mode from functioning. I used restore point and sleep mode works fine. After installing the update, sleep mode does not work, computer goes into hibernation. I am using Windows 7 64-bit. Note that this update is part of a large number of updates for March 2012. I installed each of the updates separately in order to isolate this one which causes the issue with sleep mode.Seth Thomas

Hi, Firstly, based on my research, the update KB2641653 is for security and it may not be related to this issue. Please also check if there are any other changes during that period. Meanwhile, in order to determine the issue, please let us know the following, 1. Do you mean that Sleep button is missing from Start Menu or cannot be clicked? 2. Do you mean that Sleep button can be selected, however, system goes to Hibernate Mode instead of Sleep Mode? 3. Run powercfg a in command prompt and let us know the result. If system goes to Hibernate Mode instead of Sleep Mode when you click Sleep, please try the following troubleshooting steps and see how them work. 1. Make sure the following setting is set to Never or more than 0 minute. 2. Create a new power plan and see how it works. For more detailed information, please refer to, Sleep and hibernation: frequently asked questions Power plans: frequently asked questions Hope this helps. If a post solved your problem, click Mark as Answer on the post. If a post helped you, click "Vote As Helpful" on the left side of post.

Jeremy, Thanks for the response, but I am not going to reinstall the security update which I did twice already to test. I just posted this so if others had the same experience Microsoft could look into and fix the update to avoid this result. But to answer one of your questions, I did not lose my sleep option which I initiate with a shortcut on my desktop. It just didn't go into sleep mode - hung for a long time, then went into hibernation. Seth Thomas

Similar problem with the last batch of updates. Put the computer into sleep mode, go to wake it up and everything sounds like it's waking up but the display doesn't resume. also found there was a problem with hibernation. Put the computer into hibernation than go to restart it and it looks like it's going to resume, but then stops on a blank prompt screen. Restored the system to before the install and everything works fine.