First of all it is not virus but it is modified and then used by virus. Autorun.inf is the primary instruction file associated with the Autorun function. Autorun.inf itself is a simple text-based configuration file that tells the operating system which executable to start, which icon to use, and which additional menu commands to make available.
eg: whenever we insert CD/DVD a small window pops up and asks what action to take it is basically done by autorun.inf file. now the virus simply modifies it so that it executes the virus intentionally.
Here is a way to manually remove it if antivirus fails. type the following code in notepad :

cd\
c:
attrib -r -s -h autorun.inf
del /q /f /s autorun.inf
d:
attrib -r -s -h autorun.inf
del /q /f /s autorun.inf
e:
attrib -r -s -h autorun.inf
del /q /f /s autorun.inf
f:
attrib -r -s -h autorun.inf
del /q /f /s autorun.inf
g:
attrib -r -s -h autorun.inf
del /q /f /s autorun.inf
h:
attrib -r -s -h autorun.inf
del /q /f /s autorun.inf
i:
attrib -r -s -h autorun.inf
del /q /f /s autorun.inf
j:
attrib -r -s -h autorun.inf
del /q /f /s autorun.inf
k:
attrib -r -s -h autorun.inf
del /q /f /s autorun.inf
l:
attrib -r -s -h autorun.inf
del /q /f /s autorun.inf
m:
attrib -r -s -h autorun.inf
del /q /f /s autorun.inf

u can also change the code depending upon the drive letters u have in this code drive letters included are c,d,e,f,g,h,i,j,k,l,m u can add or reduce some.
Now save the file with name Clean.bat now click it to remove the autorun.inf file.
Basically this code will unhide the autorun.inf files and then delete them.