i would check the setting ot that realtek network card .
This is a great idea as well. Reset the settings to default and run the troubleshooter! Make sure your DHCP is set to automatic.
I tried the CCleaner. Fixed the registry issues the program detected. Still not solving my issue. This issue happens to all of my network cards (wired, wireless, Vitualbox NIC). So I think it's Windows related issue, not NIC related.