1) Doesn't matter if it is an on-board NIC - it is still someone's chip and
only in a about half the cases is it actually the same as the motherboard..
Intel, Broadcom are common chipsets to be integrated into others mainboards.
What is it under the Device Manager?
2) Sometimes a patch to fix a hole in Windows/other OS can close something a
driver was taking advantage of (knowingly or unknowingly) and a new driver
might be needed - thus you should always check the manufacturer's site for
the latest driver if you start having trouble. Try the mainboard
manufacturer's web site first - follow that up by checking the chipset of
the NIC's manufacturer's web page for the model of the chipset it showed in
(1).
3) When was the last time you scanned for malware?
Reboot and logon as administrative user.
Download, install, run, update and perform a full scan with the following
(freeware version):
SuperAntiSpywarehttp://
www.superantispyware.com/
Reboot and logon as administrative user.
Download, install, run, update and perform a full scan with the following
(freeware version):
MalwareByteshttp://
www.malwarebytes.com/
Reboot and logon as administrative user.
Download and run the MSRT manually:
http://www.microsoft.com/security/malwareremove/default.mspx
You may find nothing, you may find only cookies, you may think it is a
waste of time - but if you do all this and report back here with what you
do/don't find as you are doing all of it - you are adding more pieces to
the puzzle and the entire picture just may become clearer and your
problem resolved.
Reboot and logon as administrative user.
Your "I have tried uninstalling / reinstalling it in device manager" without
searching for a newer version of the driver reminds me of the quote,
"Insanity is doing the same thing over and over again but expecting
different results." *grin*
One thing that could have happened - a driver update accepted from Microsoft
(who had nothing to do with the manufacture or current support of your NIC.)
Another things - things can and do go bad over time - could be that
component is doing just that. Network components can get surges just like
electrical components can. ;-)