Yeah these virus are made in VB
and most of these VB virus used the autorun.inf to be executed (including maskrider and Fujack)
so that they can be autoplay if u double click the drives.
Thru antivirus these virus are deleted but autorun.inf remains there..
so ur drives remains in autoplay condition and since virus r not there so ur drive is not
being able to open directly.
If virus r there and u delete autorun.inf then it wil again be created by the virus running in process.
and also one more thing most of this virus are hidden in recycled folder (which act like recycle bin) in my computer.
So u can also manually delete the virus if u wish...