It gets great speeds (~30 MB/s) when connected directly to the router via ethernet, so it's not my ISP. The speed appears "typical" (6-12 MB/s) on my laptop, on my phone, and on another laptop, so I'm pretty sure the WiFi is as good as can be reasonably expected. This computer gets "very slow" speeds (0-2 MB/s) via WiFi.
It would seem that the laptop itself is the problem. It has been a bit temperamental about wifi ever since I bought it last year. In an old apartment, I needed to be RIGHT next to the router or it wouldn't work and it would never connect to public hotspots. I thought it was because this is a refurbished machine, and the wifi card must have had some problem, probably a bad antenna. So after I moved, I bought an external, USB wifi card, which should be better because external antennae are usually better than internal ones.
That hasn't really solved the problem. It can get WiFi now further away from the router, but it's still slow. it was okay until recently (since I don't stream or game much), but recently it's gotten even worse.
Other things I have tried:
-- multiple virus/malware searches, which turned up nothing fishy.
-- started firefox with add-ons disabled
-- tried IE instead of firefox
-- tried Chrome instead of FF
-- updated my drivers
-- updated the firmware on my router
-- checked my task manager for any unusual program running in the background, but nothing stands out
-- turned both this computer and the router off and on a zillion times
None of this has improved the situation more than a tiny amount. Any ideas?
Update: setting to 802.11b gets her 5.6 MBps, which has stopped the nagging (for now).