I use firefox and IE, all my caches and temp internet files have been deleted (and are each time I end my session). 2 weeks ago I had a hard time with the PM box, figured out it was the mass email that was sent to everyone. I deleted all my PM's (which took forever because each time I clicked the screen, the program would stop responding) and the problem seemed to disappear. Today I log in, can't load the site again - I try to open in IE and go to my PM box.... All the messages I deleted are back, inculding the mass email.
I can't open the box enough to delete anything and I don't really have time to be messing with it everyday.
Just wanted someone to know incase it's happening to anyone else. Good luck!