I don’t know how, but my boot target drive recently changed which I fixed under system preferences. However, everytime I boot my machine now Safari opens. How do I stop this?

It’s strange that your boot drive randomly changed, without question, but I’m suspecting that you started up at one point and the standard hard disk was unable to spin up before the system bailed and switched to your secondary drive. Fortunately, you figured out that you can go to Apple –> System Preferences –> Startup Disk.

To change what programs automatically start up when your computer boots up (actually, the programs automatically start when you actually log in to your account, but most likely your system is set up to automatically log you in when you start up your computer) you need to go to a different area in System Preferences.

This time, go to…