I had this last week took me 2 days to find it, as none of the common virus/malware software got rid of it! It was hidden as a Java plug in, found and disabled it in safe mode. The only way I found it was going to the microsoft website and running a full service scan (free) that detected it after several hours but could not remove it! but at least it showed me were it was.
I tried so many different methods but none of them touched it, but stumbled across the Java thing and follwed the posters on screen resolution and its fixed it.
This nasty little bugger starts off as a Spy Tool trying to sell you software whilst disabling your installed antivrus, after a while it stops this and starts redireting your google searches, no idea were it came from though.
The claw, thats because you have not got rid of it, just doing a recovery still leaves the trojan on your PC.