I'm using J2SE Runtime Environment 5.0 and I currently have 4 updates on my PC: 3, 6, 10 and 11. Can I remove the first three without affecting the program function?
I think that the currently update is important for your browser! You can try a reinstallation!
Yes, you can safely remove the previous updates without affecting the program function. For this purpose, I suggest you use Java Uninstall Tool which will detect the Java versions installed on your computer and remove those that are out of date. Also, you can remove the first three updates through Add or Remove Programs Feature (Control Panel > Uninstall a program).