Mac OS X 10.6.8
Safari 5.1.5 (6534.55.3)
I have Flash 18.104.22.168 installed. Certain websites are now not loading at all such as my internet provider www.orcon.net.nz, however many other websites are loading perfectly fine. Video is now no longer playing at www.tvnz.co.nz/video - the page will load fine but when try to play video it is blank. YouTube video appears to be playing fine but before everything else stopped working we were having trouble with videos stopping part way through. I am not really clear on which websites use flash and which don't so I am sort of presuming the problem has something to do with flash as I know that tvnz on demand does use flash. Nothing 'crashes' or gives any error report, just doesn't load.
I have tried basic things such as uninstall/reinstall flash, clearing cache, running repair disk permissions in disk utility. Internet line speed has been checked and is fine. Have tried installing firefox and chrome but makes no difference using these browsers. As you may be able to tell from my question, I don't really know what I'm doing so any suggestions for solutions in easy language would be appreciated.