good stuff (and some advice)
Well done - an excellent article.
I encountered similar problems with a friend's computer - they downloaded a rogue spyhunter app to deal with a long-time resident dialer - the rogue was NOT detected by Norton 360 - it intoduced a number of trojans which ...
a) redirected google searches as you state;
b) replaced the desktop image with one sta\ting the system was infected;
c) prevented browsing to anti-virus sites such as aVG, f-secure, trend micro etc.
d) prevented existing a/v tools from updating.
I downloaded various apps with another computer and brought them to the infected machine with a USB key.
Uninstalling Norton 360 took about 45 minutes - very slow; AVG installed OK but would crash on scanning the boot sector.
Various other apps (from f-secure etc.) would not run unless I changed the executable name e.g. from fsbl.exe to fslbabc.exe and even then wouldn't execute properly.
So what worked ?
Malwarebytes' Anti-Malware app executed and found 39 trojans/malwares in a few minuted - it deleted these
Gmer found another two (but its not for novices and I was reluctant to use it to remove one)
SuperAntiSpyware was slow but detected another three
and finally AVG (now able to run) found another one (only 4 hits in Google and all dating from Aug 26th) that the others failled to find.
... and all these apps will be run again tonight!
Good luck and thanks again for a superb analysis - apologies for the non-specificity of my own notes above re exact versions/trojan names etc.