I updated my 2007 non-unibody Macbook Pro with 4gb RAM and 2.2ghz Core 2 Duo. It successfully installed, then the spinner froze on boot and the computer wouldn't start. I ended up just reinstalling Mavericks from scratch and starting over. But now, a few days later, I was just doing random stuff and the computer froze. It usually isn't a problem and has never been a problem for me before. This time, when I rebooted, the spinner on the boot screen froze again, and it just sits there for 5 minutes then shuts off. I can't boot in safe mode and I don't want to reinstall Mavericks and all my apps from scratch again. Is there anything I can do to get this thing to work??? Any commands I can run from recovery? Thanks ahead of time!
UPDATE:
I booted into recovery and restored from the most recent Time Machine backup. It told me to reboot so I did, and then I got this message. I didn't boot into verbose, it just did this. http://pastebin.com/rFaUtWfN
Best Answer
After four days of testing, I found out that it was when I turned off the wireless (Airport). My laptop would totally freeze within seconds and every time I would try to reboot. When it still froze even after I rolled back to 10.8 I knew it wasn't a hardware issue.
I found a fix on day 5: Do not turn off your Airport, Turn off your modem!
Seriously, if it happens to you, get your Mac on target mode and browse your hard drive to:
and rename the file "com.apple.airport.preferences.plist" to something like "com.apple.airport.preferences.plist~bad" and reboot.