Grey progress bar appears under apple logo during startup. When progress bar seems to complete the process the Mini CPU switches off. Not sure what caused the problem, but the Mac mini was recently upgraded to the latest OS x version 9.5.1. The only previous issue I had was running out of RAM, however this was solved by upgrading from 2GB o 4GB RAM.
Mac mini, OS X Mavericks (10.9.5), Intel Core i7 2 GHz RAM 4 GB
