Did you try this:
Click on Start, and at the search area, type: cmd
Right click the command file, and select: Run as Administrator
At the command prompt that appears, copy/paste the following:
attrib -h -r -s /s /d g:\*.*
Note: Assumed your USB drive is g:
If not, please replace the letter g with your USB drive letter!
Now, check the files in the USB drive...
If no-go, try the following:
Download Unhide.exe to your Desktop:
If the file does not download, copy/paste the following link >without brackets or quotes< in the address bar of your browser:
Right click on unhide.exe and select: Run as Administrator
For XP, double-click on Unhide.exe
Allow the program to run.
This program removes the hidden attribute from all the files on your hard drives.
Let us know how it goes.
There is probably an underlying virus that you need to get rid of.
To be on the safe side, you could do the following:
Download iExplore.exe, which is renamed copy of RKill:
Save the file to the Desktop.
Right click, and select: Run as Administrator
Ignore any messages, and allow the file to run until the command window closes.
Now, download Malwarebytes’ Anti-Malware (black button with green and white icon)
Save to the Desktop:
Double-click mbam-setup.exe and follow the prompts to install the program.
Run Malwarfebytes’ AntiMalware and update the program.
Once updated, select Perform Full Scan and click the scan button.
When the scan finishes, click OK in the message box, and you will see the results of the scan.
Click the Remove Selected button to get rid of the malware.
When Malwarebytes finishes, you may be prompted to reboot. If so, reboot.
Please post the Malwarebytes log in your reply so we can see where we are at, and plan any additional removal strategy, if necessary.
Retired - Doin' Dis, Dat, and slapping malware.