My Wifi keeps kicking off after upgrading to 12.04. I can connect for a few seconds, then it kicks me off over and over again. I'm using an older Thinkpad T41 with Intel Pro/Wireless 2100 built in. I have used this laptop for MANY years and with MANY distros with no problems at all until now. I got this thinkpad with this Intel wireless card specifically because it IS supported by the linux kernel. I upgraded from 11.10. and it was fine since 8.04. I even installed gentoo on this back in the day and that was also fine...
It seems to be working fine now. I opened the network manager (edit connections) and saved the password in wireless settings and it seems fine... I may have done a few other things as well along the way so I'm not really sure how this was broken/fixed...