I've just installed C7 on my netbook that already contained Win7 (and also Fedora 19, which the C7 is intended to replace).
If you want "dodge" a fight with grub, you can install EasyBCD (to windows OS) and handles multiple systems. (you can found a trial version):
http://neosmart.net/EasyBCD/ I use it to handles 4 os tell me... Pol _______________________________________________ CentOS mailing list CentOS@xxxxxxxxxx http://lists.centos.org/mailman/listinfo/centos
