Like Allan said a lot more information is really needed.
But I'm going to make a WAG anyway.
When upgrading Flash, sometimes all previous versions of flash need to be deleted (through the add/remove programs in control panel) before the new version can be downloaded.
And I'm not sure any browser is better than another when it comes to flash. There is a reason Apple doesn't want anything to do with flash, but most of us are kind of stuck with it, and all in all it's really not that bad.