If you did not format your drive, then check whether the files are not in
Click on "Start" -->Run-->type cmd and click on OK.
Here I assume your drive letter as G:
Enter this command.
attrib -h -r -s /s /d g:\*.*
Now press enter.
Note : Don't forget to replace the letter g with your drive letter.
Now check for your files in that drive.
After that, download the Malwarebytes' Anti-Malware from the below link
Update it --> Perform "Full Scan"
Note : Default selected option is "Quick Scan".