Customer moves house, uses dial-up for a few weeks, then goes back to broadband, but the PC won’t connect to the net.

A swap of PCs, shows that the internet connection is fine, but something is wrong within the PC. It looks a lot like a faulty network card, but it seems to get a dhcp ip address correctly…

I take it back to the office… and it works just fine on my wireless usb adaptor. I clean up some spyware (favoriteman, winfixer, drivecleaner), then I plug it into the ethernet… but that won’t work.

I try booting ubcd4win, but it also cannot see any network.

I’m just about ready to install a new network card, when I decide to try a linux live cd (mepis).

While it boots in verbose mode (by pressing F2), I notice a strange error… something like: invalid mac address detected : 00:123:45:67:89 please complain to your hardware vendor.

I take a look at the bios, but there doesn’t seem to be a way of altering or resetting the mac address.

Ok, I go into control panel -> system -> hardware -> device manager -> expand network adapters, r-click on the network card -> properties -> advanced -> network address… then I enter a “random” mac address (I pick my routers address, and alter 2 numbers slightly).

and it now works!