I use google literally hundreds of times a day for work. When autocomplete became compulsory, it just about drove me around the bend. I went off to google forums to complain, and found help. Someone provided an extension that defeats autocomplete.
Since I use google as my home page, this was easy; I just set it in Firefox to be:
http://www.google.ca/webhp?complete=0&hl=en
When I try to change the .ca to .com for you down there, the url gets converted to this:
https://www.google.com/webhp?complete=0&hl=en
i.e. it ads an s to the http. It's hard for me to test because google simply will not allow me to go to plain old http://www.google.com; it converts it to .ca no matter what I do. (I can get to .co.uk and .com.au and so on with no problem, just not .com.) So try that link with and without the s on the http and see what it does.
... I dunno, I've never bothered to fix my home page in IE to the no-auto-complete version, and it's giving me https://www.google.ca as my home page now; I'd never noticed an s there before. Ah. Is this because I'm signed in to gmail accounts in both browsers maybe ... and oh fuck, in IE (which I use only to have spare gmail accounts open, and I've just realized I don't even have to do that now, so bye bye IE very soon) I am now getting instant bloody search, too. What have I done ... ?!?
The ways of google are strange and mysterious, and I hate almost all of them ...
edit - aha, when I C&Ped the url for .com, it came out without the s on the http, so I guess that's just there when you're signed in to a google "product".