I have tried 3.0.621 on computer where previously was installed 2.7. 621 was working properly and after test I have uninstalled it. After reverting back to 2.7 I find that firefox have issues with Java, which I never noticed before - it will randomly shut down, if several tabs with Java open and closing one tab. Installing back 3.0.621 solved the problem, but it is not a solution. Are there any cleaning tools or instructions available, or something is damaged at driver level?