What Have I done?

That is correct

Commodore Pet said:

That is correct

Yep.



When you swapped the PSU, you didn't reinstall Windows did you?

Because if you didn't, then the drivers for the LAN should already be installed.

So with the drivers installed and the LAN enabled in BIOS, does it show up in Device Manager >Network Adapters and if it does, does it show a warning triangle and a error code in the properties?

kodi said:

For correct air circulation Fans on the Front and Side blow air IN and fans on the Top and Back blow air OUT

My case is designed to suck air in and blow air out
no fan is needed to suck the air in due to the vents underneath and on the back side of the case.....and when you run a processor that runs at 45 celcius and a video card that runs at 75 celcius at full load...both have fans you can not have a fan suck air into the system....the processor and video card both pull hot air off the heat sinks both my fans blow the hot air out of the tower. with the vents no need to suck cool air in cuz it will just suck more dust in than usual and that causes extreme over heating.

It actually does not.show up at all its as if it was never there at all I did not re install win7 all ibdid was swap over the PSU (and cut a hreat hole in the top of the case LOL). That is why it is strange because it was fine until the swap over

Do the ethernet port lights at the socket come on at all?

It's starting to sound as if the on-board LAN might actually be dead. (Old PSU hurt it / damaged during removal - re-installation back into case)

no lights on the back at all . Was thinking it might be dead at my first guess but thought i might have done something wrong though

Lack of lights is indeed a bad sign. I'm pretty certain it's dead mate.

Oh well it could have been much worse i suppose Thanks