I have noticed some problems when people don't realize they have Windows Defender running along with other programs of the same type, and those conflicts are often over looked because Windows Defender does not stick out like the other programs do with the bloatware and such.
I am not sure why you have the purchased version of Malwarebytes when the "on-demand" scan does the same thing for free.
Basically you only want to have a virus scanner running full time.
One that automatically scans a file you download from the web and makes sure no malicious code is embedded in any emails you open.
As for malware scan tools, the program should be set up to run only when you execute it to scan your drive, or a questionable file. Other than that, the program should be idle, and not scanning all the time.
It saves on system resources as well.
Edited by MrBruce1959, 12 April 2010 - 11:24 PM.