I kept trying things, but wasn't getting anywhere and the symptoms started to get worse - I'd get random freezes and other weird lock-ups. So I finally gave up and moved back to 10.10 (which is working fine on another laptop).

I was rather surprised when I encountered the same problems (completely clean install). Some searching finally uncovered the fact that the driver for the wireless adapter (Ralink RT3090) in my netbook is flaky (putting it mildly!). It often causes crashes on shutdown, suspend, or when adjusting networking. I "assume" this was probably my problem when trying 11.04. If I upgrade to 11.04 sometime before too long I'll post a follow up (For now I just disabled the internal wireless and am using a USB wireless, and everything's fine).

For those who are interested, the bug report (https://bugs.launchpad.net/ubuntu/+s...x?comments=all) shows it's being worked on, but it doesn't appear to be completely resolved yet (though a few people seem to be able to get it working right).