As I said earlier, unless you have the installation media (Windows on a DVD or bootable USB so long as your motherboard supports booting from USB devices) to either perform a repair (if that even works) or a clean installation, there's not much you can really do here. Judging by the bugchecks from earlier and knowing the history now of the OS (drivers being updated with unsupported/3rd party software), it's no doubt that the OS is pretty corrupt at this point.
You can try and boot from safe mode, disable all non-essential startup items/programs so random 3rd party drivers aren't hopefully being loaded on startup, but that's really about it.
The lesson here is to always:
A: Have installation media in some form as discussed above.
B: Ensure you have a proper working product key.
Microsoft doesn't give out ISO's for Windows images anymore without providing a product key, so if you have legitimate alternative means of obtaining installation media (friend, family, etc), you can always do a clean install of Windows and worry about activating it later after you get the product key situation sorted.