Installing Windows on BOOTcamp with iMac

Hi,
Ive upgraded my Mac OS to Yosemite so my version 8 of parallels no longer runs. I want to setup a bootcamp partition and run Windows 7 because i game i just bought runs to slow.
Every time i try to run Windows setup parallels starts up and tells me it won't work with Yosemite.
Is there a way to disable Parallels temporarily so that i can get windows 7 on Boot camp without having to uninstall Parallels.
Thanks,
Mike

 

You're doing it wrong, that's not how you install Windows on Bootcamp.

http://support.apple.com/en-us/HT201468

However you'll need a DVD/USB with the actual Windows installation image, not the Windows Setup which just serves to download the installation image on a Windows computer (upgrade Windows).