I have a Dell Dimension 8400 that is no longer under warranty (i.e. no phone support). I am having trouble connecting to the internet. Sometimes it works (not as well as I'd like speed-wise), and sometimes it doesn't. I'll be online and it will say a network cable is unplugged while I am surfing (when it isn't). Then that message will go away after a little while on its own and connectivity returns without my touching anything.Sometimes I'll be opening an internet page and it will take a couple of minutes before the page starts loading even though it is showing the internet is connected.

I use Roadrunner (high speed) with a modem connection. I've had my cable company out here and they have replaced all the cables and the modem. They say the signal is fine (and it is since I can hook up my laptop with no issues) and that the problem lies with my PC. When I called Dell, the guy thought it might be my NIC card - that was before they realized phone support had expired. My system has an Intel Pro 1000 Integrated PCI NIC Card.

I am not technically savvy with terminology and so forth, but I've learned a lot as I've worked on my PC during the years and I always like to learn more.  I have no experience with NIC cards. Is there a way I can test my NIC card performance? Since it is integrated, if there is a problem, do I have to replace the whole thing? Are there other things that could be causing this problem that I could check? Could anyone offer me any assistance? I would prefer to work on my system myself due to monetary concerns. Thank you for any help you can offer.