Please include/list your specs like so:
You might also want to state why you're having to disable driver signature...unless you're trying to force drivers onto the platform it's not meant for. Might I ask where you sourced the installer for Windows 7?
If the driver's signature enforcement option is enabled, it means your computer can only be installed by digitally signed drivers only. If the driver's signature enforcement option is disabled then you can install it without digitally signing drivers on your computer. This is the difference. There is a particular option in Windows 10 to disable the driver signature, see this video:
If the NVIDIA official driver is not digitally signed then no one can do anything apart from NIVIDA guys. But if you have downloaded it from its official website then you can use it without it being digitally signed, there are no issues, I think.