autorun.inf dissapears

Chances are that the autorun is still there. Try this:
- open notepad
- click "File", "open"
- go to the drive's location
- in the file type box select all types
- in the filename box type autorun.inf
- click open

If that doesn't work then here is a simple autorun you can do:

[autorun]
open=StartPortableApps.exe
icon=StartPortableApps.exe

Save this file as autorun.inf (be sure to change the save as type to all files)

Another thing it could be and I hope for your sake it isn't is a virus. I picked one up at Tafe once where my autorun seemed to disappear. Anyway to cut a long story short the virus had changed the autorun to hidden and changed the instruction in it to run an EXE or BAT (I cant remember which) that it copied onto my usb. Then when the autorun did (sometime) work instead of Start portableapps the autorun handle was simply run this program and had a blank icon. Not sure what it did specifically but basically had to junk the usb and my home computer.

the autorun.inf virus is horrible!
Run Flash Distincter if needed!