Sun and Microsoft both now recommend making sure that you have the latest version of Java, and Sun gives assurance that the current and latest version will run any Java instructions ever written. Because they will no longer patch earlier versions, and numerous vulnerabilities have been found in most of the old ones, both companies recommend just deleting all the old ones.

I haven't seen any feedback from users indicating that getting rid of the old versions has caused any problems.

In IE, at the little "gear" widget on the same bar where your current URL shows at the top (or at Tools if you've turned on the "Menu bar) there's a selection for "Manage add-ons" where it's easy to turn any of them on or off temporarily. If you haven't looked there, you may not realize how many add-ons you have, and might want to just remove some of them, or turn some others on/off. Other browsers should have someplace similar to manage them, but I don't use any of the others enough to advise.

John