I have a 13″ mid 2009 MacBook Pro.
For a long time now my browsers just decide to stop working. The 1st occasion Safari kept crashing every 10 minutes so I downloaded Firefox but after a while the same thing kept happening.
I thought it was something to do with Flash so I downloaded a newer version of Flash but that didn't solve anything. I then downloaded Chrome which was fine for a while but now from time to time any browser I use just stops working. I find myself either having to switch my wifi off and on and restart which ever browser I'm using or if that doesn't work, when Safari stops working I switch to Chrome and vice versa.