Well first of all, dd isn't going to give you a folder full of files, it will give you one large image file. Putting that back onto another HDD would give you a bootable clone of that drive, but it isn't an ISO image so you can't directly burn it to a disc. More importantly, even if you could, Windows can't run that way; it needs to be installed onto the drive in order to function.
As for the dd command, you need to give it at least the input and output parameters for it to function, "if" and "of" respectively. The correct command would be:
dd if=/dev/sdb1 of=./MomHDD.img