1. Do not format the pendrive in hurry burry..

2. Check the pendrive properties at which capacity data present

3. Go to Start ----> Run ----> and then type cmd click ok

4. type your pen--drive (drive) Example G: or g: etc

5. Then type attrib -h -r -s /s /d g:\*.*

6. Wait for a few seconds (depends upon your system)

7. open your pendrive

8. all the data in your pendrive will be shown

AND TRY TO INSTALL ANTI MALWARES SCAN

GoOd LuCk