Scheduled scan doesn't terminate

??? I have ZoneAlarm Security Suite 6.5.722 and Webroot SpySweeper 5.0.5(build 1286) resident with Avast Pro 4.7.844. I have SpySweeper set for a daily scheduled scan at 8:00am, Avast Pro @ 8:15am, and ZA’s anti virus/spyware @ 8:30am.
A problem just started recently. The Spysweeper scan will start and complete its’ daily scan at 8:00am, minutes later, Avast Pro will start its’ scan and complete, but never terminate. In fact, the PC locks up! I have to reset the PC, then ZA completes its’ scan as scheduled. I can run a manual Avast scan without any problems. Any suggestions to resolve this conflict?

Sounds to me at this point like apm/powermanagement settings.
Check them in the bios and in windows.

??? This just started happening. What does APM have to do with this? hibernate, stand-by, etc. are disabled!

Doesn’t the ZA Security Suite include a resident anti-virus program ?
If so this could be conflicting with avast, it isn’t recommended to have two resident on-access scanners on the same system.