- Yes, and
- either will work.
Note that you will need to let CentOS replace you MBR, and use the Linux boot loader to start your Windows system as well as your CentOS one. Also, you should be careful during the installation: If you pick the incorrect partitioning scheme, the CentOS installation might reformat your hard drive, wiping out your Win 7 drive(s).
You should have a full Win 7 backup, offline, before starting the installation, and make sure that there is enough free space (unallocated to any partition) on your drive. (That assumes that you're installing CentOS on the same drive as your Win 7 system. If you have a second drive available, life is much simpler.)