I'm having the same problem.
It may be a problem within google, but for me it's gone much farther than that.
The second I opened up my browser, a new tab opened and "advertised" a fake anti malware.
I'm not going to rant about my issues here, and considering you've had no responses in a month, I'll see if I can help.
Download and install that, please.
Although It hasn't picked up anything on my end (and it should have) it might do something for you. Remember to update it after installing it. I'll have you know, that you may have other malware on your computer not related to the redirecting. I know I did first time I had downloaded Mbam.
This redirecting issue (and random tabs opening) has me a bit P'd and intrigued and I will look into it for the both of us, and will report back here when I've got something worth knowing.
After doing a quick scan(or full. Quick is usually sufficient though) please copy and paste the log here, and regardless of how well I think I know computers and malware, regardless of how much I actually know, I like to see what malware people have....It's like a hobby of mine
Have a happy holiday buddy.
Peace, Love, Cheers,