Wireless Internet problems

This is doing my head in, so any help would be great.

I've got wireless internet with Virgin Media. It connects to my
laptop and says that its "excellent", then when I'm surfing the next,
I'll get a "Problem Loading Page" message on my browser (Firefox) and
then my Windows Live Messenger will discount, (I have two and one will
normally stop before the other) and then finally my Skype will
discount. It does this on and off a far bit, sometimes it won't do it
at all and other times, like now, it'll do it all the time.

My internet appears to stay connected, at least where it says
"duration" it shows hours rather than minutes.

When I try and connect my Messenger again I normally have go through
the troubleshooter and that shows an error with the DNS and Key Ports
(#80072ee7). Sometimes one Messenger will connect find but the second
won't and I'll have to go through the troubleshooter.

As I say, any help anyone can give me would be great because it really
is making me mad!

Cheers

Simon