I am not familiar with the notepad trick, but you should really just buy a legit key for Windows. If this is Windows 10, it is already very forgiving on activation, and should take a legit Win 7 or Win 8 key as well. Regardless, there are quite a few keys you can buy for much cheaper than retail on certain sites such as ebay etc...
As for the fix, of reverting back from the notepad trick, I am not sure, but I suppose it is possible that your laptop is infected, given the windows was not activated. I would do some anti-malware scans, and consider doing a fresh install of Windows after backing up your data. If you already have a backup image or even a system restore point, you could just roll back to that point.