What version of Java are you using? Go to Start > Control Panel > Java > click on the General tab > click on the About button. Then you'll see which version of Java you're using.

Also go to Control Panel > Add/Remove Programs & see whether you have more than one version of Java installed.

Try reinstalling Java: Java SE Downloads
Download the JRE offline installer & remove any other Java versions installed (via Add/Remove Programs) before installing the new one. Reboot your computer after installing Java.

Otherwise, try the other fixes here: http://www.gnutellaforums.com/window...ng-should.html