Cache problem with firefox

on the Imageboards Firefox has taken to remember exactly how pages were.... this means if i replyed to a post firefox would show the page EXACTLY as it was before i posted. I figured out it was the cache which was doing this so i cleared it.... however everytime i want to go on 4chan i would have to clean my cache before i could view anything. The only extension i have is the most recent version of the 4chan extension and its never done this to me before in the years ive had firefox.
Im running 1.5.0.4

Im also not switching to Opera because ive already tried it
In before www.opera.com

Make a new firefox profile and see if the problem still occurs when firefox is using the default configuration.

If it works with default then you probably fucked with something in about:config, and should either backup bookmarks and make a new profile, or fix your current profile

If it doesn't work, go to mozilla forums or irc and ask there. Search the mozilla forums/faq and google first.