......Java 6 Update 26..
And yes, uninstall ALL previous versions.. Try using the instructions below to perform the task:
Click on the link to Sun's Java below, then scroll down to the ''Java Platform Standard Edition - Java SE 6 Update 26'' section, then click on the "Download JRE" button. Follow the prompts, select the Windows platform and the "Language", if necessary, accept the license agreement, click the "Continue" button, 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 ''Programs & Features'' section, then uninstall all previous versions of the J2SE Java listed there. Once that's done, then install Java JRE 6u26 from the downloaded installer.
(Yes, you can try the newest Java 7 JRE download if you'd like but since it's a brand new release, you might want to wait a little while for the bugs to get ironed out.)
Hope this helps.