I just bought a second hand mac pro 5,1 (mid 2010) with no hard drives and no installation CDs. I bought a 120GB Samsung EVO SSD. I am waiting on an IcyDock to connect the SSD to hard drive bay 1. In the meantime I'm using an extention sata cable to connect the SSD to the motherboard (HDD bay 1) and powering it via a power adapter to sata power. I've formatted the SSD using my 2008 iMac to extended (journaled). I've inserted my Snow Leopard disc (that I bought years ago) into the optical drive restarted the mac holding c to boot from CD. I hear the disc spinning, the white background with gray apple logo appear but nothing happens. The disc stops spinning. Background stays. ??? Am I doing anything wrong? Does the macpro side door have to be closed? I've contacted apple about needing the original installer discs and they said I could just buy Snow Leopard and use that. I already own it. Another symptom: If I unattach the SSD and restart the mac holding the mouse button on, the DVD drive doesn't open. It only opens with the SSD attached.