I rarely have any problems with my Mac starting up, but because we have a number of Macs in our home office, and we've been using Macs since the Mac Plus, I've seen my share of startup issues over time.
When your Mac freezes, stalls, or fails to utter even a beep, you may wonder what to do next. That's why I gathered the top 10 troubleshooting tips for startup issues. There are many more than 10 possibilities, but some startup issues are rare enough that they don't make the list anymore.
One example of a rare problem is a memory error that can prevent your Mac from starting up. Instead, it just makes the power on LED blink to get your attention. To fix this, try resetting or replacing the RAM.
For just about everything else, take a look at: