Big Chromebook/Google account mess - old boy needs help please!

Si_Clist

At my age I should have known better than to be setting up a new smartphone when I was likely to be distracted by an irritating tradesman making a mess of the house, but anyhow,  I've got myself in a big mess here.

I was trying to log in to an app on the new phone, and for reasons which I can't recall now I ended up having to set a new password for my Google account.  Which was fine until I later opened up the Chromebook and had to enter the new password, which I did.  Then, after being distracted bigtime, I somehow found that Google then wanted me to enter my old password, which I couldn't remember.  I think it then offered me the opportunity to do something anyhow despite some files not being saved, so I (foolishly) went along with that.

Before all this, I signed on to the Chromebook with a PIN.  Now I have to enter the new password manually every time.  And when I do, I find that all my files have disappeared!

I don't recall ever being asked if I wanted to back them up, so AFAIK they're not backed up anywhere.  Is there any hope of me being able to get them back?  Is there perhaps a magic button somewhere I can press called "Go back to how things were before you screwed them up"?