If Windows 7 does not contain your drivers, you may have to install them yourself. Some of my devices will not install because they are new, but it sounds like some drivers are missing. I will unually install the lastest version of chipset drivers, and any I think might be more specific than any Windows 7 ones.
Once you install the basic drivers, Windows may update them, if it has not already.
An OEM install may be different that other Windows 7 installs, and I am not sure how having a hard drive where the Optical drive is might make a difference. Did you make any changes to the bios after swapping out the Optical drive?