No worries, it`s not asking much for members to conclude their threads when assistance is no longer required but it is even more important to get signed off with malware related threads to remove the possibility of spreading any infection/s to other computers etc.
Download then run Speccy (free) and post the resultant url for us, details here, this will provide us with information about your computer hardware + any software that you have installed that may explain the present issue/s.
For some reason your OS is shown to be in the grace (evaluation) period something that shouldnt be happening on a computer that has had the OS installed since as you explained "a few years back" try the suggestion made by FreeBooter and if no joy after that use the telephone activation procedure that I have copy/paste below;
To activate Windows 8.1 using the phone:
Select the Start button , enter PC settings, and then select PC settings from the list of results.
Select Activate Windows, and then select Contact customer support for help. Administrator permission required You may be asked for an admin password or to confirm your choice.
Select your location (or the location nearest you) from the drop-down list, and then select Next.
Call one of the available phone numbers listed. An automated system will guide you through the activation process.
The above only takes a couple of minutes and should only cost the price of a local call.
NB: If phone activation doesn't work stay on the line and you should be transferred to a Microsoft Activation Team operator.