A couple little corrections should be made here...
First, Spybot USED to be a substantial program, but it's gone downhill over the years. Avast is definitely better, even though I never recommend it (personal reasons). Secondly, Comodo AV is pretty useless, as it's way too paranoid, and flags way too many things for the average user. If you want a new firewall, Comodo's FIREWALL is a good choice; just use the firewall though... that's about all that's worth using.
As far as antimalware goes, HitmanPro and MBAM are always a good pair to run in conjunction with a quality AV. If you do a lot of downloading, browse unknown websites a lot, or you aren't very careful with what you do on the internet, then weekly scans are a good idea. If you're actually quite careful, then bi-weekly to monthly isn't going to hurt you.
But yeah, it's nice to hear this was just some random text to speech mishap. Definitely would suck if there was something malicious going on.