How to unhide the deleted files by WinRAR

Hi. My friend came to me with a query that he scanned his Flash Drive with AVAST AntiVirus, which detected some malicious. He just marked all the files with deleted option and press the continue button. When AVAST deletes the files so it actually hides those files. Now he says that he had some important files, which are also (deleted) hidden there. Now the data is all hidden in his USB but it does show the space when he checks the size of the Flash Drive.

I normally use the way to open the Flash Drive in WinRAR and from there i extract them to some new folder. I've done all this and the files have been all extracted in a zip format. But when i extract the file to get my data, so it extracts it but still does not show data? :(:(:(. Please guide me how do i display them. I've even selected SHOW ALL HIDDEN FILES from Folder Options but still not working.

I don't use Avast, but any antivirus has an option to restore deleted malicious files.

How. :(

Read this topic it may help you.