My Acer M5811 will not wake up from sleep mode on intermittent basis. Running Windows 8 Pro 64 bit. Power settings are disabled for both the monitor and CPU. I have also disabled "allow computer to shut off applications to save power" to devices. I never had this issue until I installed Windows 8 (clean install) from Windows 7. I have updated all drivers but have had no luck. The computer will wake up successfully several times, then it will not wake up. It appears to start up but the monitor remains in sleep mode. The only way to fix the problem is to shut down the computer and then restart. Any suggestions? Acer M5811, purchased May 2010; i760 processor; 8 GB ram, ATI Radeon 5570, 1TB hard drive.