Windows 7: Can I stop automatic shutdown from terminating running applications?

I have used a power option to hibernate/shutdown my desktop after (say) 2 hours. This works correctly so that the system does not shutdown automatically when I am running interactive applications, .



At least one scheduled weekly task (McAfee virus scan) can take many hours and I normally run it overnight. But when it is the only task running, the PC hibernates (apparently after the prescribed interval) even though the application is still running.

I do not want to change my power settings to prevent automatic hibernation completely or to lengthen the interval meaninglessly. So:

1. Is there any other way to ensure that the virus scan is allowed to complete before the system hibernates?
2. During a scheduled scan, McAfee has an option to run "in the background". Would cancelling that optionhave the desired effect?

1. Open a word document or start a presentation with PowerPoint (or similar programs). That will keep the computer from hibernating and won't use any amount of resources (well, a few hunderd mb of RAM).

2. It could, it won't surely hurt, as the main difference is that if not running in the background it will gobble up more CPU for itself, making multitasking harder. If it runs on its own, it's better to uncheck that option anyway, as it should be faster if not running in the background.

Thanks - I will try both suggestions and see if either will work on its own.