i appreciate the info thanks. I had MS Security Essentials and Malwarebytes (run manually a couple times a week). I previously dropped Zone Alarm when a laptop I aquired with Vista would not run with ZA, so I started using MS Security Essentials on the PC and the new laptop. After about a year the PC computer quickly became unusable, all security programs were disabled and would not run. I was able to boot disk a couple new AV programs that found trojans, exploit stuff and others. I was able to run Malwarebytes in safe mode eventually, it found a couple items. Right now the computer takes forever to load on startup, won't connect to the internet without resetting modem etc, and when it does connect most IE addresses are redirected to sites selling software or other computer stuff. I ran scans with the specialty software recommended from this site and had the logs ready to post when I saw the recommendation to reformat rather than continue down the cleaning path. I've been spending today getting the laptop with Vista protected so I don't lose the one functioning computer I've got. I've installed Kapersky Internet Security and have been very happy with how it performs with Vista. I like the "vuneralbilities" scan besides the regular scan. It showed me software, windows settings, etc, that needed updating or were at risk.
I'm getting ready to remove docs, music and pics off the infected computer for reformatting.
Thanks for your input. The infected computer in question is 6 years old so I'm also conidering scrapping it, but for what we use it for, I think it still has the necessary performance. Spending a little more time on it may be worth saving $800.