When I used win 7 I had the exact same problem I use the 64 bit version it also did the same thing in vista 64.

You have to realy zing the wheel to get it to zoom. I have the microsoft natural wireless 6000 one of microsofts top mice, I plugged in a cheapo logitech mouse and the zoom worked as it should. I opened a ticket with SCS and they told me it was a driver issue with Microsoft they have version 7.1 out now but it changed nothing

I went back to XP cause I need the mouse for my wrist and also I use the wheel all the time.

Anyway try a different brand of mouse and see what happens.

I hope that Microsoft and SCS can work this out because I really want to use Win 7.

Paul B