First scan with Kaspersky antivirus. Then search on google RRT.exe( Restriction removal tool) which is free and will restore ur folder settings. I think that u r using pen drives frequently. My tips for u are-
1. Do not open pen drive usning double click. Use e: or f: ...
2. whenever u see autorun.ini file. delete it.
3. sometimes virus is like a hidden folder having name microsoft power point.exe. do not double click it. right click it and scan with antivirus or delete it.
OR
some virus might have changed the registry values. If you are an adiministrator, you can edit registry. You must be careful inediting the registry.Type run>regedit. Registry opens. navigate to -[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\SHOWALL]. On the right side you will find "CheckedValue" if dword value is : 00000000 it must be a virus. Change dword value to :00000001. you can find folder options. Also check the startup items and if you find amvo.exe in the startup (msconfig) your system is infected by this virus. remove it manually.