IPhone got reset after it was plugged into the computer.what to do?

I connected my iPhone to my PC. After I disconnected it I found out that everything (including pictures, music, etc) has been removed. I think the cellphone has reset the whole thing.

Can I recover the files or are they gone. Is there anything I could do?

There's probably a backup on the computer. Look for an option to Restore.

It may also be backed up through icloud. There's an option to restore it from icloud in the initial set up steps.

Of course, you can use DVDFab iFoneRestore data recovery software to recover them if this unlucky things happened to you.It is really very powerful app.