difficulty with avast rescue disc

hello every one
i made a rescue disc with success(it was said)and i got a win.RAR iso disc which is not launched at starting of pc(the windows7 disc is functionning at the start of pc);i tried to decompress the win.RAR iso on my pc and i burnt it on the rescue cd without success at pc launching.what is the problem

The problem is that you didn’t create the rescue disk.
Copying the iso to a cd/dvd is not how it works.
http://forum.imgburn.com/index.php?/topic/61-how-to-write-an-image-file-to-a-disc-using-imgburn/