I have Inspiron 3537, 6GB/ 1TB HDD existing, I want to upgrade it with a WD 240GB SSD. I have bought a Caddy  which will take place of DVD Writer. I have installed 240 GB SSD in place of HDD,while i have installed the HDD in the caddy. I have installed OS in SSD ( At this moment caddy carrying HDD is not inserted in laptop). When I inserted it Caddy, it is showing in boot menu but it is not reading the disk.

Also the Vice-versa proceess was carried and it was found that the PC boots  only when single SSD  or HDD is inserted , then only laptop works fine. If inserted both , it doesn't works.

Note: There is No defect in Caddy.

Please Help