Hardwire Problem

[hockeysticks]

I have an Acer Aspire 1830T-3425 laptop.  It works wirelessly with wifi but for some reason it won't work when I hardwire it.  I know it's a problem with the laptop because  have hardwired my other laptop and it works fine.
When I open the local area connections, there are 2 listed.  One is: tap win32 adapter v9 driver and the other is: Atheros AR8151 PCI-E Gigabit Ethernet Controller.  The former has a red X beside it.  It says that the ethernet cable is not connected properly or is broken.  But it works fine on my other laptop.

I've tried everything from rebooting the laptop, powering off and on the modem and router, installing the driver, etc etc.  Nothing has worked.  Any suggestions?  It worked up until about a month ago.
THANKS

[DaveLembke]

The former has a red X beside it.  It says that the ethernet cable is not connected properly or is broken.  But it works fine on my other laptop.

Knowing the Cat5 cable is fine when connected to another laptop, I'd say that the NIC on this laptop is probably damaged or dirty. What condition are the gold pins in, also if the cable locked into this RJ45 port without play or does the connector in the laptop wiggle at all?