My Macbook Pro (mid 2007) will not go to sleep.

Question

When I close the lid, select sleep from the  menu, or push the power button, and select "sleep" my MBP will not go to sleep as it ussually does.  It has been doing this since I performed the last set of software updates (Mac OS X Lion 10.7.4 (11E53) about a week ago. 
I need help... this is annoying

Answer 1

This is for a Mac that won't sleep.
Here is Apple's  KB article HT1776 with their tips.
Mine follow;
USB devices and hubs often cause Macs to not sleep or wake quickly from sleep (notably HP printers and scanners, HP all in ones, and Cannon scanners). Disconnect all USB except for keyboard and mouse and try. If it sleeps, add one back at a time testing after each one to find the culprit.
If you've set your Mac to receive faxes, it may not be able to sleep. It might also have a damaged preferences file. If you use your Mac for faxing, open System Preferences. click Print & Fax, click the Faxing tab, and uncheck the Receive Faxes On This Computer box.
If that doesn't work or you've never faxed on your Mac, go to Finder/Hard Drive /Library/Preferences/SystemConfiguration and delete the com.apple.PowerManagement.plist and com..apple.AutoWake.plist files (if your Mac asks, type your admin. password). If the latter file isn't present in the folder, go to user name(probably your name)/Library/Preferences, delete the com.apple.systemuiserver.plist file, and reboot your Mac.
Some have resolved sleep issue by downloading the Combo update, from this site (yours may be corrupt), not Software Update  disconnect all firewire + USB devices except keyboard + mouse,Repair Permissions, re-install update, Repair Permissions again + try
USER TIPS……..
Check in System Preferences > Energy Saver is "Wake for network access" checked? If so, uncheck it.
One user reported, " I couldn't make my macbook pro to go to sleep because I had my wireless headphone receiver still plugged in. I unplugged it and then it went to sleep."
Also, if you have an External Western Digital (WD) hard drive and have installed  WDDMService and WDSmartWareD on your Mac, it may not sleep. Fix is to un-install those....you don't need them to use the drive.
"I have had this problem with my IMac G5. It is surprisingly irritating. LaCie's Silverkeeper backup software was the cause. By default it gave itself permission to wake up the computer to check if a backup was needed. Do you have this or a similar program installed which has scheduled activities including wake-up permissions as an option?"
One provided this link, xlr8yourmac.com, to a member, which addresses failure of deep sleep with some users that updated and added new FireWire and USB card.
Also, here is Apple KB article TA2469 about PCI cards and sleep.
After few days of messing around I found out that I had desktop background (wallpaper) set to change every 1 minute. After unchecking "Change picture..." in system preferences (under Desktop/Screen saver), my powerbook went to sleep all by itself.
"I  have a Canon printer(shared) and my imac would not sleep. I opened up printer/fax in system prefs and noticed it said the printer was in use when it was off. Opened up the printer queue and noticed about 7 pending documents. Deleted them all and now it sleeps. Check the printer queue!"
One user has had success, after trying all these tips, using an App. called PleaseSleep. I've never used it though.
Good Luck! 
DALE