Hi @superstina; welcome to our Community and thanks for using Dropbox!
Assuming that you're looking at the correct account and if those files were indeed syncing before you changed computers, there must be a sign of them on our website.
Can you let me know if you can see them anywhere in your account online and perhaps try accessing a previous version of those files to see when they were edited?
While we're at it, you can also take a look at your events page as this is the place where all uploads, edits and deletions are normally logged.
Keep me posted on your findings!