This is my first time asking for help with network problems online, so bear with me.
We've (we=family) been having internet connection problems with one of our computers. The computer with the problem happens to be our desktop, the only computer in the network that is using a LAN connection. All laptops/iPods/TVs/etc. connected to the wifi network are working properly.
The connection problems have been steadily getting worse over the last few months. The first problem was with an online classroom. Although the computer appeared to have no other connection issues, I would be disconnected from the classroom server several times throughout the class. It was as if there was a short break in the internet connection every 10 minutes or so. Eventually, we noticed that links wouldn't always work the first time we clicked on them, and this began happening more often. Now, we're lucky if we can get a page to open on the first try. It often takes multiple attempts to get a page to load.
As further proof of a connection problem, YouTube videos only buffer about 5 seconds. After the 5 seconds of video have played, we have to click beyond what has buffered in order for the video to reload and buffer another 5 seconds. The same problem happens with downloads. After about 5 seconds of downloading, the downloaded amount stops increasing, and the estimated time remaining begins quickly increasing. In order to get a file to download, I have to click the download link, wait until the file stops downloading, cancel the download, click the download link again (the download picks up where it left off in Google Chrome), allow it to download for another 5 seconds, and repeat the process until the file is completely downloaded.
We recently replaced our router to fix our decreasing wifi range and speed. The new router works properly and our wifi is back to normal. The desktop is connected to the router as it doesn't have a wireless card (the desktop is a Dell Inspiron 530 from 2008, running Windows Vista 32-bit). Unfortunately, replacing the router didn't solve our connection problems on the desktop, so the router wasn't the problem. I've used multiple cables to connect the desktop and router, thinking a bad cord might be the issue, but that didn't work either.
According to the device manager, the network card (Intel 82562V-2 10/100 Network Connection) is functioning properly and has up-to-date drivers. Diagnosing the network in the Network and Sharing Center shows no problems. Basically, according to the computer it's internet connection is fine, but it obviously isn't.
I've looked around the network settings to see if anything looks wrong (although I probably wouldn't notice if something was), but everything looks all right to me. I've tried tinkering with settings based off of troubleshooting tips I've read online, but since nothing worked, I set all the setting back to the way I found them. I've disabled and re-enabled the network card in device manager. I've done pings and tracerts and anything else I could think of to try to pinpoint the problem. Nothing but the symptoms seem to show up.
My guess is the problem is either the network card or the LAN port. If a USB wireless adapter would bypass the network card altogether, I think that's our best chance of resolving this, since the wifi is working properly. However, before I go buy a wireless adapter, I thought I'd see if anyone has suggestions.
Ask for any tests, specs, etc. As long as you're willing to walk me through any tests I don't know how to do, I'm willing to give any results that might help diagnose the problem. Thanks for all help in advance.