MacBook Pro - Spinning Ball of Death - PLEASE HELP!!

Hello,

I have a MacBook Pro (2011, I believe), and every time I turn on my computer (in the last 24hr), the spinning ball of death pops up. Sometimes I can access an app like Google Chrome or Microsoft Word or Text Edit before the spinning ball appears, but the most recent time, all I did was start up my computer and it froze on the spinning ball of death. When this happens, I cannot click on any other icons or apps. I cannot access "force quit" via mouse or keyboard commands. The only thing that works is a hard shutdown by pushing the power key.

If I need to just purchase a new computer, any ideas how to get my files off of the computer and onto an external hard drive?

Any information would be GREATLY appreciated! Thanks in advance!