Could be S3 issues + devices edit: including Drivers or corruption from all those sudden shutdowns. I assume that you went to the MOBO website, downloaded ALL of the Drivers and installed them. Also that Windows 7 is SP1 with all the Hotfixes installed. If you somehow screwed-up the Drivers then open the Device Manager and right-click on all of the Drivers listed {expanding the [+] trees} -> select Update Driver.
Corrupted files CMD Prompt {run as administrator}
sfc /scannow
Sleep problems CMD Prompt {run as administrator}
powercfg -energy
copy the energy-report.htm to the desktop and open as located in the report ; ignore the USB stuff if you have a Keyboard, Mouse or All-in-one card reader.
Lastly, to rule-out a Conflict run MSCONFIG -> select Diagnostic and allow the PC to Sleep if this corrected the problem then you've got the task of finding out where the conflict is.