Lately a drove of end users have called to complain that IE wont work on their machines but any other browser will. After closely examining these machines, I have identified the issue as lsp.dll, bundled with Imesh, ShopAtHome and other shady internet software.
I sent in the findings to the SpyBot folks and as of today they have a signature that will catch and remove this problem.
For more info on the actual nasty that causes IE not to be able to resolve hosts, see:
http://www.pestpatrol.com/PestInfo/s/sahagent.asp
Anyway, just in case others get a large line of angry end users...
--TH13