CentOS

I recently created a dualboot system, windows 7 and centos 7.

When I boot in CentOs my Windows drives mount too, I dont want that. I want to keep the OS's separate. Cant I disable this somehow?

In the file /etc/fstab you will find an entry for each of your Windows partitions. Add noautoto the options field (4th field on the line).
The option defaults implies "auto". With the noauto option in place, the partitions will not be mounted automatically on boot or when "mount -a" is called, but you can still mount the drives manually if you feel the need.