Ethernet shield--Can't enable Network Sharing (pi-top)

For months, I've been trying to get the Ethernet Client example to work. When I was using a normal computer, and the usual Ethernet connection from shield to router, I got and error saying COM3 was busy. Then later, there was no router I could connect to, so I enabled network sharing on my computer, and connected it to the Ethernet shield using a straight-through cable, which I'm pretty sure was a mistake, and I got a bunch of errors relating to java script, but now I have a crossover adapter, but now I'm using a pi-top, and there seems to be no option of enabling network sharing. I swear, there is at least one thing wrong with every single aspect of the pi-top.