Network Adapter problem

Hi all,

I am installing vmware esxi 5.0 on a machine with following specification:

RAM:8 GB

Processor: intel(R)core i5-2400 cpu@3.10 GHz

Network adapter: 1 x 1GB                      Intel(R) 82579LM Gigabit Network Connection

Hard Disk: 500 GB

Operating System: Windows 7

while installing i got error :

either your network adapter in not physically connected or install driver, or you may install third party driver.

but network adapter is physically connected in my machine.

pls help me in resolving this problem.