Malwarebytes is a great tool and one more that I cannot recall right now. It is not well known but it works well along with hijackthis.
In addition to these tools you can use netstat command at dos prompt with different plugins to see what is causing connections to which IP and what processes, etc.. Where anti-spyware software like ad-aware or others fail, thats where netstat comes in and allows you to fix issues... of course it takes longer and very tedious work!
We had breakout few months ago where a malware program that infects windows WMI service took over 40+ end user PCs in one location and spread across site-to-site VPNs to other remote offices. After running Trend Micro Corporate AV, ad aware, etc. with no luck and no way to track down what was slowing down the PCs, DNS was totally screwed up on those machines, exchange was acting funny... it was "fix the issue" paradise. We ended up using netstat commnand to track down the sucker and took us about 5 days to clean up around 100+ workstations.
I don't understand how anybody could crash/corrupt their hard drives with a malware crap. In my 10+ years of IT experience and at least 16+ hours a day in front of a PC, I've never crashed or corrupted a hard drive of PC that I use. I've fixed PCs that had spyware/malware issues that others installed unknowingly = user error!!!