Windows XP
 Firefox 26
Dell Dimension 8300 (yep, old)
user..yep old
Charter  IP
modem, wireless
 A few weeks ago this same problem occurred  then got better. Not sure if I fixed it or what happened.  Problem is back and worse.
 Firefox will load, AOL, my homepage, will not load..or only eventually loads  text, no graphics.
 Facebook will not load
Cannot connect to AOL mail
 Weather sites, etc. No Load
 Pogo.com  loads a bit but not fully. This site fine
Control F5..no results
 cleared cache, cleaned up everything I know to clean, ran antimalware , ran tweaking repair, chkdsk,  updated all.   
 reboot, swore, threatened...no luck
 Hubby  has same computer, runs firefox,  uses charter for mail.  He can access some sites but not facebook, and weather etc.
 Charter installed new modem a week ago. System was fast and fine... but now this
 No reset button on modem
 My samsung galaxy 2  will access AOL mail  most of the time...some new mail does not load  and part of facebook but no graphics.  
I did have an unmountable bootvolume  issue that I fixed...no more problems with that.
 It is time for new computers but  I want to get this figured out..can't access any sites to comparison shop ! 
Any ideas???  I am not savvy in terminology  so please talk down to me. 
Many thanks