Help!

I discovered by accident today that all my scheduled tasks (such as
some important nightly backups) were no longer working. On
examination, the Set Password box was empty for each one. I entered
and confirmed them all - but on later re-opening Properties, the
password is blank again.

FWIW, the Run As box contains TERRY\Terry.

How can I fix this please?

--
Terry, West Sussex, UK