PC drops internet connection (on a network)

[ACiD303]

I've been experiencing web drop outs, or long connection "pauses", on my main computer for a while. I've been blaming Virgin Media for this initially, however I have just realised that none of the other computers on the network suffer from this (there are 4 computers in total, hooked up to an old Netgear router).

I've tried changing the ports on the router, switching cables, updating the network card driver to the latest (it's the onboard controller I'm using on a Gigabyte P35C-DS3R), tried looking at the events (there was nothing) and I can't think of much else now

What's stranger is that the PC isn't dropping the connection altogether - I'm using WinVNC to use another PC to write this post from my main PC, so even when the internet stops working, the connection is still live. Also, I'm never signed out of MSN either. So it seems to be just a web problem.

I didn't have this problem to start off with, but it only seems to be getting worse - I don't have a connection for about half the time I think....it's being somewhat counterproductive :s

edit: not sure if "drops" is the word, but it acts like a DNS cannot be resolved...

edit 2: I think it may have something to do with Firefox, just tried IE and that worked....?

Help appreciated!