Let us start presuming only good and positive direction first.
The system has its on inbuilt checking mechanisms .This is mostly done when we start the computer, or when we plug in some other device to it. Many of what happens is not known to us as they happen in the background.
As you are using the original version, Windows update takes place automatically. Probably after one such update, the system would have found some incompatibility with the hardware or software existing in your system. The system itself fixes that problem or alerts us what to do about that. It may be this routine thing that would have happened with you. That is the main probability, if you are otherwise keeping our anti virus software update, not transgressing to unknown web site, not installing software or extensions from untrustworthy or unknown sites.
If you ave doubts still, try to 'system restore' to a date when you are sure nothing has been done or changed since. So in case some system change happened without your know;edge, that may be cancelled.
However if hacking was the issue,then the general symptoms will be as given in the previous answer post. That is your computer may 'misbehave', or work extra than what you commanded, or will not obey your commands at all.
But I do not feel any such thing has happened.
Now, start your computer,without connecting to internet. Open the files you usually work n, open some files you do not open generally , open and seethe important documents which have sensitive information etc. If they are functioning fine, then close all and connect the internet, Now,do only updating the anti virus software. Then do a full scan . If the result shows no threats, then you can feel safe. However for abundant caution, you may open your mail and check for any abnormality. If the mail is loading normally, the net speed is as usual, then there is nothing to worry as you feared.