Is there any way that someone could have entered the course direction into the computer from a remote location?
If it can connect to a network it can be hacked.
The article says there are two ways - the pilot and the airline. However if it was the airline, that would be quite a big conspiracy - saying that the airline wanted to divert its own plane. And ... if that sort of thing happened, with the pilot not being “in on it” - then he would take control and override the control.
In this case, you can be assured it came from the cockpit and that it was someone who knew very well how to handle the equipment.
No
This article
http://www.express.co.uk/news/world/465126/Missing-Malaysia-Airlines-plane-may-have-been-cyber-hijacked-using-mobile-phone
Claims it could have been hacked from a usb port in the cabin seating area... considering the 777 is a fly by wire plane. It is talking about using a mobile phone, but if that is true, I would think the right hacker with his custom laptop might even work better and could possibly link up with flight simulator software if that were the case...
The whole idea seemed a little far fetched when I initially read it, but this article seems to possibly legitimize the possibility.