I also upgraded my old thinkpad r40e from ubuntu 9 to 10.04 and the pc hangs with blank screen, no keyboard/mouse, and no drive activity. It hangs randomly but appears more often if I use firefox instead of google chrome. I can however get back the pc if I remove my pcmia linksys wifi. Then reconnect the linksys and pc continues from where it got hung as if nothing had happened. This pc runs fine before the upgrade.
I also upgraded my old thinkpad r40e from ubuntu 9 to 10.04 and the pc hangs with blank screen, no keyboard/mouse, and no drive activity. It hangs randomly but appears more often if I use firefox instead of google chrome. I can however get back the pc if I remove my pcmia linksys wifi. Then reconnect the linksys and pc continues from where it got hung as if nothing had happened. This pc runs fine before the upgrade.