SOLVED Can't retrieve emails

[testy]

My PC has developed an issue where I can send emails, but am unable to receive. I know emails are there; I can check them as webmail on my provider's site; I can retrieve them via my laptop, but my PC always returns:

I have scanned for viruses, including a boot time scan, and have tried three different email programs; my usual is Mozilla Sea Monkey, I installed Thunderbird, and tried Live Mail as well. All give the same response.
I'm hoping the error message will mean something to someone. My limited knowledge suggests that the problem is between the PC and the server, rather than between my email program and the server.

 

[testy]

Finally figured this out. My provider's server settings had apparently changed, or at least I found they are different to what I've been using, when I checked on their website. I don't understand though, why the old settings are still working on my laptop. Same provider, same account. Anyway, problem solved.