I have norton 360 and an Inability of my Computer Going Into Sleep Mode with Win 8

I have norton 360 and an Inability of my Computer Going Into Sleep Mode with  Win 8 after any scans.

I have to reboot the machine in order for it to go into sleep mode.

I noticed this after installing Win 8 and Norton 360.

There are no user controls that I can find to try to eliminate this problem.

Any help would be greatly appreciated .