I have a virus all my files are in .ppvt

Hi favian, thanks for bringing this to our attention.

From what you described, it's possible you might have ransomware on your computer. 

Could you try these steps to help on your account?

Keep me updated with any progress!

How can I eliminate the virus because it is inside the drop box, that is, it is not on my laptop, it is on the dropbox server

There aren't any viruses on the Dropbox servers, unless the virus is one of the files in your Dropbox account or folder. 

You'll need to remove the virus using the normal antivirus scanning method, and then look into the article provided.