Loss of internet access may be PUM.Bad.Proxy malware

MajorGeeks.com has helped me a lot, here's a contribution to our crowdsourced experience:

I got a call from a responsible customer that internet access was down. Customer's ISP phone support had tried to get it back and failed. The machine was behaving normally otherwise.
Long story short, it wasn't a problem with the Ethernet port. MBAM found PUM.Bad.Proxy, which blocks IE (Internet Explorer) from using the 'net. Wikipedia has a good article on this problem.
MBAM, Microsoft's Safety Scanner (MSERT), SuperAntiSpyware, and AVG found nothing else amiss.
We are not sure how it arrived, but I note this customer uses Outlook Express. O/S is fully patched XP Pro SP3 32-bit, antivirus is paid AVG.

KGHN Feb 2014