I really hate to hear that. But, you are a brave one for wanting to hook up a previously infected disk to one that is pristine.
Apparently, once the dl.exe is downloaded onto your machine and opens its backdoor up, it attaches its own code to your executables. The creator probably didn't wasnt to trash your machine just turn it into a bot. Personally, I wouldn't trust any executables on that disk. Best thing is to fdisk it and reformat.