BTW, I have used Malwarebytes for years, always keep it up to date and I do run it at least once a week.
Will download that FileHippo update checker and run it. Also I was behind on Windows XP updates because if I leave the setting on automatic it always slows my computer down when it finds new updates. So I usually just check once a week but have been slipping lately. There were several security updates that I downloaded yesterday.
I'm still puzzled as to why Avast didn't find those trojans when I did a scan a couple of weeks ago. The redirect viruses have been around for a while so they should have already been in Avast's definitions. Oh well. Hope that's the end of this stuff. Thanks again for all your help! I'll post again if it reappears. Take care.