Tried booting in safe mode and testing the speed on both Internet Explorer and Google Chrome. The results were unchanged from before.
I also tried unpugging the ethernet cable from my desktop and, without changing where it was connected on the other end, plugging it into my laptop. On the same network, I tested the connection speed again and found it to be about 40 Mb/s for downloads, with the same upload speed as before. So I don't think it could be the cable or ISP.
And then I also tried booting into Ubuntu onto my desktop from a flash drive and running a speed test on that. It was blazingly, incredibly fast; about 200 Mb/s download speed and 40 Mb/s uploads.
In light of all this, what could be causing such painfully slow internet in XP?
Update: I tried it again at 7:20 AM, when figured usage would be down. Still got about 0.5 Mb/s.
Edited by dpitch40, 01 February 2010 - 08:24 AM.