Currently I'm using Windows 7 Ultimate, at the very beginning, everything went pretty well, but these days, there is something wrong about the Network Adapter---Every time I log in to win7, the network icon shows it works properly, but actually I can't connect to the Internet.
So I tried to disable the Network Adapter and reenable it, and the Network starts to work.
I really don't know what the problem is...
Isolate if this is an issue with the hardware or software...
My suggestion is to boot your PC in safemodewithnetworking.
* If the issue is not present while in safemodewithnetworking look for a driver update for your network card.
* If the issue is present while in safemodewithnetworking - try switching ethernet cables and switch/routerports
* If the issue is still present after updating the driver and switch cables/routers - Try using the same ethernet cable on a different PC or Laptop.
* If the issue is not present using a different PC or Laptop - Backup your files you may have a corrupted OS or a faulty network adapter. Proceed on reinstalling your OS with caution
Make sure your modem/router isn't flaking out on you.
I've seen issues like this that may seem to be isolated to just the computer,
but I've seen failing routers/modems cause all sorts of weird issues.
If you have a USB LAN adapter, try that. If it works fine all of the time then
you either have a driver issue or a faulty network interface device.