A little update.
I have now tried connecting the PC directly to the wall ethernet port, instead of through the router. I have also tried dolphin in Ubuntu (14.04), which is also installed on my desktop. Neither have yielded any new results. My conclusion is that it has to be hardware related, but as it didn't work through my mobile connection either, I don't think it's the actual network device.
I am completely out of ideas myself now. If anyone has anything that I could do to in any way get closer to the source of the problem, please don't hestitate.
I have now tried connecting the PC directly to the wall ethernet port, instead of through the router. I have also tried dolphin in Ubuntu (14.04), which is also installed on my desktop. Neither have yielded any new results. My conclusion is that it has to be hardware related, but as it didn't work through my mobile connection either, I don't think it's the actual network device.
I am completely out of ideas myself now. If anyone has anything that I could do to in any way get closer to the source of the problem, please don't hestitate.