Code:
extract the Isoinfo.7z file into temp folder
Done!
e.g: on my computer, I extract it into folder named Dirt3 --> F:\Game\Dirt3
the iso of the 2nd disc is D3_2.iso
and I put this iso into the folder Dirt3, too (as you guided).
Code:
the open command prompt ( start>run>command )
Done!
the command window shows like this: c:\user\anhlinhp4>_
(but I don't know what to type next...)
Code:
change to the temp folder you made earlier ( copy the iso for dirt3_2 there to )
Don't know how to do!! (sorry, I'm so stupid here)

Pls teach me this step.
Code:
then run the command that peter put in the box ( but use your DIR )
Don't uderstand how to do!!

Pls teach me this step, too.