I know this tread is old but for someone reading this like I did this may help.
I ran into this issue and on windows XP with IE8 and had the same exact problem. I went to java.com and download java button was missing as well so It's not java. Turns out the computer was infected with a trojan which caused the problem. Once I ran a system restore, it fixed the issue. Malwarebytes picked it up and deleted it.