Problem downloading mail via Airport

Hi guys,

Well I am a bit new to the MAC world, though I have been using an iPhone for almost a year now.
Anyway, I got this Mac book which was working fine for a couple of weeks but then, it just stopped getting mail both on the Mac mail and Entourage, it simply gives me an error message that the server is timing out. I had a look around on the forum and tried turning off the firewall, nothing. I tried putting WPA on my wireless ( 3COM) router, nothing. In short nothing I do helps except connecting the MB to the router with a wire. I did a test today and installed Parallels and tried to get my mail there with Exchange ( on an XP virtual) and well.... no problem, but at the same time I was getting a time out in MAC OS.
Now the PC guy in me says f..... it, just install the full featured outlook in the virtual OS and use that, but then why the **** did I bother getting a mac for.
I tried Apple support who talked me through putting the install disk in, booting from it and fixing the permissions on my HDD, they said that if that did not work, we may have to reinstall the OS !X?!!!@%$ I don't think so.
Oh and it didn't work !!

Can anyone help?

If your MacBook works to get mail while connected via ethernet cable, then the problem is more than likely related to security or airport is not properly setup.

How about browsing? Can you browse web sites via airport? Post back.

Regards.

Yes I can see the internet via all browsers

and as I said, if I run parallels I can download mail just fine at the same time as I can not download mails via MAC OS, this means I have an internet connection AND I do not have any security issues from the network side.
But also, it was working fine a couple of wees ago.