Virus attack problem? You can use anti-virus software to scan your memory card on your mobile. But before doing that, you should back up your data. If you find data lost because of virus attack, 4Card Recovery is able to recover your files as long as your data has not been changed. So please recover your data as soon as possible, once it chcanged, there is no possibility to recover it.
Download 4Card Recovery for free and install it on your computer.
Run it and select all files to recover.
Scan it and save recovered files.
Have a try.