As has already been said, while it might be difficult for you because of your disability, they are asking you to use a cable to see if the problem is the WiFi or a more general one. For If you get good speed with a wired connection then the problem lies on the WiFi side of things. On the other hand, if the speed is roughly the same whether wired or WiFi then there is a more general problem as you will have then eliminated the WiFi as the problem. Without trying to eliminate, or not, the WiFi as a possible problem first, you are both just wasting each other's time and energy.
Solving problems like this is a one step at a time process, where you start with the most likely cause first, often the WiFi. Whether because your room is a WiFi black hole or another user is interfering or because of an actual WiFi fault in the router or your PC.
If, for sake of argument, we assume the problem is the WiFi, you can test for a WiFi black hole by moving the router around the room and see if you get significant differences in speed depending on location. You might be be surprised how little you have to move an unit, whether the router or the PC, sometimes to see real significant differences in throughput. You can test for interference by trying different channels.
If you don't see any difference with the above checks then it would look likely a WiFi problem and you would need either another known good router or another known good machine, perhaps a friend with a laptop, to see whether the problem is the router or the PC.
Edited by jcym (Wed 04-Jun-14 00:03:26)