Macbook unable to update from 10.6.3 to 10.6.6
I recently was given a 2008 macbook that was running OSX 10.5.3. I bought the Mac OSX Snow Leopard 10.6.3 DVD and successfully updated the computer to that version of Snow Leopard. I would like to continue updating the OSX to 10.6.6 so that I can have the app store and consequently update it to Yosemite. But every time I run system update, it downloads the software and asks to restart the computer. I restart the computer and it doesn't restart properly and gets stuck on the blue galaxy open screen and stays there. I've tried selecting "restart later" and manually starting the update but the same thing happens. I'm not sure where to go next to resolve the issue.
MacBook, Mac OS X (10.6.3)