Many strange issues with 2009 Macbook Pro running 10.10.5
My first guess would be a failing HD. You could try to look into the console.app, found here:

/Application/Utilities/Console.app


If the log shows IO-Errors it's time to replace the HD. 

There are of course other explanation, f.e. a corrupt Kernel extension or even a defective Font, but as i said it sounds like the HD.