Laptop not alt-tabbing?
Try making sure you are running the game at the same resolution as your Windows Desktop, or use Windowed mode instead.
I've had similar problems with Vista. It started when I turned Aero on and off a couple of times. I think I've got it off at the moment.
Can't get to taskbar with the Win-button or alt-tab. The only way I get to desktop from the game is hitting ctrl-alt-del and choosing task manager TWICE. The first time doesn't do anything, but the second time it brings the desktop on.
But that's Vista for you. Sorry I can't be of any help... If you've got Vista, try the ctrl-alt-del way. Or install Win7 over Vista, that might help
When I try and Alt-Tab on my laptop, it'll bring up the taskbar but won't let anything supersede the game on the screen. It's rather frustrating as I use IM programs as well as playing CoH. My Desktop does not have this problem. Any ideas and/or suggestions?