Not to change focus from AV & anti-malware, but
IainB brings up an interesting - and ofttimes intrusive - point.
I recently installed
XAMPP on an eight (8 ) GB USB stick. But every time I tried to run it, it complained that the path to
MySQL was wrong. Hm-m-m ...
MySQL,
Apache, &
PHP had been removed from that machine. Did I have something that had been hijacking my
MySQL data? Spent a couple of days with
MBAM,
Comodo, a couple of other malware and keylog sniffers, all to no avail. Then I loaded
regedit to search for mention of
MySQL. That mention was massive! I spend a good hour ferreting out references to
MySQL, then pondering whether to delete a particular reference - not all of them were directly related. For example, more than a few were for
Open Office - a program that has not been on that particular machine for a good six (6) months.
After the registry surgery, the portable
XAMPP install worked just fine.
The thing here is that what appeared to be a malware manifestation was naught - naught

? - more than a couple of very sloppy uninstalls. The files had been removed from the hard drive, but references had not been removed from the registry. So I was getting hints of infestation, but
MBAM, nor any other detector of evil, could never have found it.
(Before someone tells me to use
Revo/
Comodo/
Geek uninstallers ... I did

. But those can do a good job only on the installs they've audited.)
Just a passing thought, that even if it quacks like a duck and waddles like a duck, it may not
be a duck.