asus z97m plus

I successfully installed Yosemite 10.10.3 on my system with these specs - Intel® Core™ i5-4690K - Crucial Ballistix Sport 8GB x 2 - SanDisk SSD 128GB - Samsung SyncMaster 2253LW connected with a DVI cable Everything works fine except Yosemite does not recognize my second monitor. My second...