Purchased a reburb Mac Mini fusion (2.3) with 4gb several weeks ago. All was well and bought 8gb from Kingston. Installed and all was well. After installing, computer ran well for many hours. Next morning, the computer was shut down for no apparent reason. Did not schedule a shut down. Searched the forum and unplugged unnecessary usb's and still shut down. Decided to check "never sleep" box and no problem since. Have run a ram test and all checks out. Looking for suggestions to fix this problem or assurance that my bandaid fix is ok and will not lead to long term problems. Really don't understand what is going on!!! Any assistance would be greatly appreciated.