I'm running Windows 8.1 64 bit.
When I plug in an SD card or USB drive into my computer all the files and folders are replaced with .lnk files with the same name as the original. In addition, all the files and folders are hidden, and I don't seem to be able to unhide them.
This does not happen every time I plug it in, but it happens fairly often. The motive behind the lnks is clear when I look at its properties. Here is an example of what one looks like replacing a file named splash.lua:
%SystemRoot%\system32\cmd.exe /c "start %cd%splash.lua & start %cd%wyNdYUwEdFccnce.exe & exit"
It is starting another hidden file which is the virus.
I've run full scans with Malwarebytes AntiMalware, and Avast free Antivirus, but they found nothing. I even tried Malwarebytes AntiRootkit, and it found nothing either.
Possibly related to this, a folder appeared in the root of both my hard drive partitions called $Recycle.Bin. I've heard of other people with this identifying it as malware, so I figured I should mention it.
However, the thing that worries me most is that if I didn't notice that the files were .lnks, I would have no idea anything fishy is going on at all. My antiviruses said nothing, and there's no reason to think I would have a virus.
Is there anyway to be sure there is no malware at all after I take care of it? For all I know, someone could be recording all my passwords and everything I type and I would have no idea.
Thank you very much.