Some time ago someone asked on Linkedin Question - how to remove a spyware/adaware. My answer was selected as best and here it is :
I spent nearly 3-4 months of work time last year cleaning Spyware/Adaware and Trojans..
Virus per se are not existing anymore, worms are really scarce and mostly a dead bread.
Now how to Get rid of 'em?
Lavasoft/Adware - some what decent detection, but awful at removal
Spybot - is a good as its support is - very limited - therefor detection and removal are only mediocre.
I tried AVG on several machines but I wasn't really impressed.
Both Norton, McAffee and CA are not even worth mention - completely useless and waste of your time, since being most popular they are prime target for anti-detection.
Best tools are manual (and FREE!!) ones - HiJackthis, Autoruns and LSPFix.
In some cases even booting in safe mode spyware module still remains residential and can't be removed by regular means - then the really heavy artillery comes into play : BartPE- it allows you to boot into "Live Windows" from CD - access your file system and erase ANY file - be very careful !
For Commercial products best guideline to stay away from big brands, instead find smaller, probably east europe made software - ESET NOD32 - is a great example. F-Prot and Kaspersky are decent choices as well.
But Best commercial spyware removal package so far i worked with is Webroot's Spy Sweeper - HIGHLY Recommend IT! Too bad even Trial ver doesn't do removal...
Oh eah, almost forgot - Microsoft Windows Defender - is ABSOLUTELY USELESS, POINTLESS I EVER SAW. I NEVER witnessed A SINGLE detection from it, even on most spyware infected machines. It's Update engine always gets broken for some reason. Needless to say - STAY AWAY!!!
P.S: Sometime, then new breed comes out, neither of tools can remove it, thou some still detect something fishy - Nod32 is good example. In this case - best course of action is Google the name of module of that pest and see if specialized removal tools are available - sometimes even Symantec makes decent single threat removal tools...
