Safari & Firefox Crashing

[itinvolves]

Last night my Firefox app kept crashing randomly. It crashed about 12 times on pages as complex as Facebook and as simple as Google. It would never stay open past a minute or two so I tried Safari and it did the same thing. Anyone have any ideas that might fix the problem???

[richard.mac]

try resetting safari, clearing private data in firefox and deleting their preference files in home/library/preferences.

[itinvolves]

Ok this might sound retarded but how do i know which preference to delete. There are a bunch in there. I already cleared the personal data from firefox though.