I just installed a new network card in to a PC, since the internal network card had given troubles for a long time and fixing it costs more time than plugging in a new external network card. I bought the TP-Link TG-3468, and plugged it in one of the three PCIe slots, which were all empty by the way.
After a BIOS reset, the new network card worked just fine. The PC did have a dual monitor setup, where one monitor was driven by a Nvidia 745GTX, and the other was driven by the internal graphics on the i3-4150. Both are driven via VGA, as the monitors don't have any other type of input.
After rebooting, only the monitor driven by the Nvidia did work, because the BIOS reset disabled the multi monitor setup. I re-enabled that setting, and that setting only, back on. (BIOS Chipset tab> SystemAgentConf > IGD multimonitor > Enabled) After rebooting both monitors worked, but the new network card had stopped working. I reset the BIOS again, which left me again with one monitor, but a working network card. I tried it three times, with the same result. I did update the drivers for both the video- and network card beforehand.
Does my setup make that they somehow try to diable each other? What could be going wrong here? Any help is appreciated. Let me know if you need more info.