I had to restore a former copy of my system since the sleep function didn't work anymore suddenly... It started going to sleep but the computer wouldn't shut down..! So after i restore, of course it worked again, and today.. It stopped! I have no idea why, what can be the reason? And how can i fix it directly...
Try PassMark Software's Sleeper utility program. It's a PC Sleep and Hibernation test tool to help test the ability of PC systems to enter and recover from sleep and hibernation. It's Free for personal use.
1. In device manager or power options (I can't remember which), tell Windows 7 not to disable USB when in sleep mode.
I had this same problem with my USB keyboard/mouse, so it might be worth trying.
2. If that doesn't work, take a look in your BIOS for the suspend ACPI options. There are different modes called and it's usually set to "S1 and S3", try changing it to just "S3" and see if that works.
3. Turn off hibernate mode to solve windows 7 sleep mode issue
Control panel-->Power options-->change when computer sleep--> advanced power settings and set the following options
Allow hybrid Sleep > Turn off
Allow wake timers > turn on/turn off try both settings
You don't get it, it worked and stop working, i didn't change anything intentionnaly. If i restore an older image of my system, then sleep will work again. I checked all things mentionned already. A program must have changed something, but which, why and what? Hard question...