Now a days, whenever I start my Windows 8.1 pc the Ethernet Adapter doesn't start, whereas if I disable & enable from device manager or restart the pc then it works well. If anyone know the solution please help.
Pure speculation on my part, but we seem to be seeing a rash of these types of problems lately and I can't help but wonder if it is related somehow to a problematic Windows Update. It seems that Microsoft has acknowledge that recent updates for Windows 8 have caused issues with the operating system but they are not very specific about exactly what those issues might be. They have published subsequent updates to remove it which can be found here http://support.microsoft.com/kb/3004394
It's important that you obtain the proper version (32 or 64 bit) for your system.
Additionally of course as we know, sometimes Windows Update can in general cause problems with a network adapter when it applies a hardware update that is less than optimal for a specific device. Using Device Manger to Roll Back the driver can sometimes help in these instances.