windows - Protecting USB flash drive against viruses

I got some questions about USB FLash drive protection:

1. I'm using Panda USB Vaccine to protect my Flash drive. As far as I know, Panda's app makes autorun file read-only. Imagine
   that, my flash drive infected by virus. When I insert this drive to
   the PC that have no antivirus software, is there any chance that
   virus will be "turned on" even if it has no autorun file access?




2. How far can go flash drive viruses? For ex, I'm web developer, and I'm carrying XAMPP server in my flash drive. Recently when I
   
   insert this drive to PC that has Kaspersky Internet Security, it
   detected 2 XAMPP files as virus. (I worked on this PC about 10-15
   times. But Antivirus detected only yesterday.) It offered me to
   disinfect or remove. I selected disinfect. And KAV kinda disinfected
   these files. Is there any chance that virus can get this much
   deeper or it's just KAV?




3. Is there any portable, free antiviral protection, that will protect my USB drive (NOT PC!!) from being infected?
   Actually, I have Clamwin for PortableApps. But it's only "1 time scanner" (It's not scanning always). I mean, it will not protect if I insert this drive into the computer that has no antivirus software.
   P.S. Lets say there is portable scanner. Imagine that I inserted my flash drive into the PC that already has antiviral software. How about this? Will flash drive's antivirus conflict with PC's?

Answer

You can use USB Dummy Protect

Its a small utility for protecting USB drives from viruses. Copy it to USB drive and execute from there. It creates dummy.file file which takes all free space and there is no more space for viruses. To unprotect drive execute this utility again or manually remove dummy.file.

It is not antivirus. You could execute it in virus free environment (at your computer for example). Then when you put your USB drive into computer with viruses most of viruses cannot infect your drive, because there is no room for virus there. Also its useful only if you need to read files from your drive. If you need to write something to it you need free space on USB drive and viruses could use this space too.

Known limitation: wouldn't work if there is more than 4GB free space on FAT drive.
Solution: Format your portable drive with NTFS file system.