I have installed my wallet on my all new pc the 6 or the 7 february.
My seed came from my wallet installed on my first computer that is dead now.
I have installed the 3.0.5 version
All was right but today everything is gone.
I really don't understand
Are you sure that you download the wallet from
electrum.org?
I doubt that this is a problem with Electrum. I haven't seen a single case where the "hack" wasn't the user's fault.