Bootcamp no longer boots after creating third partition

Hello;

I wanted to add El Capitan as a third OS to my existing Yosemite and Bootcamp (Win 8.1 Pro) dual partition set up.

I have done the following:

Reduced the size of the Yosemite partition

Deleted the Yosemite recovery partition

Created the third partition

Installed El Capitan

Now, I am no longer able to boot to the Bootcamp partition. Attempts to do so result in the following message.

NO BOOTABLE DEVICE – INSERT BOOT DISC AND PRESS ANY KEY

I’d prefer to fix the bootcamp partition rather than formatting and reinstalling. Might someone be able to assist?

Thank you in advanced