Very occasionally screens in Donorfy may not display properly - e.g. panels missing from the constituent profile.
Your browser stores some information about how you have set Donorfy up - e.g. sort orders for lists, panel positions and so on - if this information gets corrupted then Donorfy may not display correctly.
To solve this problem you need to clear your browser cache (history and possibly your cookies too).
The steps to clear your browser cache vary depending on which browser you are using - this link has instructions for the commonly used browsers.
key words - blank screen