VMWare player free doesn't include all the settings that the commercial editions offer. In order to boot an iso, you must hand edit the *.vmx file and add the following settings.
bios.bootOrder = "cdrom,hdd,floppy"
bios.hddOrder = "scsi0:0,ide1:0"
Adding the above information allowed me to install fedora 21 over my existing fedora 20.
Tip: After installation, I powered the vm off. Removed the above lines and removed the fedora iso from the vmware cd drive.
