Hi Fernando,
This is not a Java version issue, rather its a certificates file that is causing the issue(not opening the workbench).
You can give a try to the following steps, which can resolve your issue:
Go to panel control
Open Java
Go to Security Tab, there u can find certificates tab. Click on it
There is Import/Export facility, so download the certificate on local machine. And them upload the same certificate on your machine.
Thanks,
Ritim