You'll want to follow this MS KB to show the hidden nics Device Manager Does Not Display Devices Not Currently Present in Windows 2000 once you can see them you can remove the hidden nics that have the same IP config info. Its a common problem and its best practice to do this on every p2v to remove old physical server hardware devices as they do occasionally cause conflicts.
What sort of vnic have you installed in the vm is it an e1000, vmxnet2,3 or flexible if its vmxnet have you got the vmware tools installed. If you have then check that the vnic is connected to the vswitch and the vswitch is connected to a physical nic. You can check the vnic by right clicking the vm edit settings, highlighting the vnic and ensuring that connect at power on and connected checkboxes are checked.
If all that is ok it might be worth removing the vnic and adding an e1000 as windows will have a driver for that so it might help diagnose the issue.