They're always on medium; I checked, and it still doesn't work... but thanks for the suggestion.
I really am baffled now though. It's frustrating because even professionals can't seem to help, either on the phone, or if we get someone to wipe everything off the computer as mentioned before. Since my last post, we figured if it's nothing to do with the computer and laptop, it must be to do with the modem. So we bought a new modem - even that didn't work!
Then, my dad bought me a new laptop (he was going to for my birthday anyway), but thought that at least that would work. But the same thing is still happening. I'm thinking the only option left now is to buy a modem from some other company or something.