i replaced my HDD on my iMac 27'' and my optical drive will not work.

so after a couple short years my 2011 27" iMac stopped working. i tried using a boot disk and had no luck i used apple support and they could not help me but gave me an appt. with a Mac store. The mac store looked at it and ran some tests and said the HDD was bad. so i replaced the HDD. boot disk still did not work. so i took it back in and had them install Yosemite as my OS. originally came with snow leopard. it failed the proximity test(common problem) because i bought a $60 hard drive as opposed to $180 from the Mac store that comes with the proximity cable. so i can either buy $10 software to control fans. or a $40 cable to make an inline sensor. im trying to get my Apps back on with my app disk. and it will not read it. it takes its spins for a little bit then spits it back out. next im going to get some canned air and clean it to see if that helps. anyone else have this problem and were you able to fix it? and how?