If you get an error like the pic below try the following:
there is also an app attached that will delete all java related stuff
Click on the link to Sun's Java below, then scroll down and click on the ''Java SE Runtime Environment (JRE) 6 Update 13'' download button. Follow the prompts, select the Windows platform and the "Language", accept the license agreement, then download the full ''Windows OFFLINE Installation'' file to your desktop,(about 15 MB), scan it with your antivirus (just to be sure it's clean). Once that's done, if you've already got a Sun Java version on the computer, open the Control Panel, double click on the ''Add/Remove Programs'' section, then uninstall all previous versions of the J2SE Java listed there. Once that's done, then install Java JRE 6u13 from the downloaded installer. http://java.sun.com/javase/downloads/index.jsp
Once Java is installed, if you're using IE7, then click on "Tools' in the upper left, select "Internet Options" , then the "Security" tab, then highlight"Internet" icon (the world globe), click on the "Custom Settings" button and change the security level to "Medium", instead of "Medium-High". If you're not using IE7, then set the same settings in IE6 to "Medium".