"HijackThis" is the name of the product.
You can see the 'difference" at Trend Micro's page and/or reviews here:
http://www.trendsecure.com/portal/en-US/threat_analytics/hijackthis.php
and
http://www.download.com/Trend%20Micro/3260-20_4-6283336.html?tag=tdw_publink
2.0.x is what it was called after Trend Micro took it over and started
adding their features.
It's TrendMicro - I pretty well trust it. CWShredder as well.
--
Shenan Stanley
MS-MVP
--
How To Ask Questions The Smart Way
http://www.catb.org/~esr/faqs/smart-questions.html