So it isn't a problem of logging on to FB , but it won't even load a page of it?
Do you have a program to clean up your system?
I use this one and it works fine , has a 1 click maint/clean up , just use it as it comes, unless you are familiar with making setting changes.
I've use this program for 8 years or so.
http://www.glarysoft.com/glary-utilities/
it is free but it may ask you if you want to get the pro, just click no and get the free version.
Do a clean up and drefrag your drive and you should see some improvements in speed.
You may want remove any old programs that you don't need or use also.