Macbook Pro with OS X Mavericks doesn't restart normally

I have a 13-inch, late 2009 Macbook Pro running OS X Mavericks (10.9.5). The processor is 2.26 GHz Intel Core 2 Duo and I have 8GB 1067 MHz DDR3 memory installed.

Whenever I shut down the computer, it won't start up normally and I usually have to go to OS X Utilities during the start up and have to repair the disk and disk permissions. I stumbled upon this somewhat random solution accidentally. It doesn't work all the time but it works most of the time. I then restart the computer and if I'm lucky the computer starts.

It's getting really frustrating as I can't seem to find a reliable solution to the problem and I've had this problem for quite a few months. While I'm working, the computer would suddenly freeze and I have to troubleshoot for hours (I'm not kidding!) just to get my Macbook Pro started.

Any help is highly appreciated! Thanks for reading.