A user reported after logging-in into Google Adsense account a blank page is displayed. This only happened in Firefox. Google Chrome and IE worked fine.

First step was to disable all Firefox add-ons which immediately fixed the problem. Actual offending add-on was AddBlock Plus.
AdBlock Plus (ADP) can be quite useful add-on, so instead of disabling it you can simply add Google Adsense to AdBlock exceptions. Simply login into Adsense account, click on ADP icon and select Disable on this page.