Error 1802 on Thinkpad T40

well im sure you have seen error:
1802: Unauthorized network card is plugged in
Power off and remove the miniPCI network card.

before. well how do you fix it? hmm, i can say its easy, but it will require you to plug out your wireless card (whether its fixed internally, or externally using a card). well in my case, i took it out by unscrewing all the screws at the bottom of the laptop, then opening the front cover of the laptop (the one with the touchpad). you will see the wireless mini card inside, which has the obvious label (such as Intel Wireless, etc). just plug it out by pressing on both sides of the clipper, and it will popup by itself. then download no-1802 from here, and extract the iso file out. then burn the iso using this. select burn iso image when asked. note: you have to extract the files out using another pc/laptop obviously :P

after burning, restart your laptop with the burned cd inside the drive. press "Access IBM" to see the boot menu and press F12 to see the boot list. select CD-ROM drive to boot into cd drive.

after that, it will drop you to the dos prompt. type no-1802 and restart your laptop by turning it off first. then plug back the wireless card back into its slot, and turn on your laptop again. it should be booting up properly by now.

then turn it off whenever possible and rescrew back all the screws and you're done!

warning: if you change your bios settings again, it might come up with the error again :(