My laptop locks up tight as a drum as soon as the SDHC driver (for my built in card reader) loads. Ubuntu 8.04 seemed to have taken care of that issue and had the SDHC module blacklisted for me so I had no issues at all. 8.10 is not so nice. You have two options.
If you are upgrading with a dist-upgrade and have NOT rebooted yet, edit your /etc/modules.d/blacklist file and add
sdhc blacklist
to the end of the file. If you have already rebooted, and hence are hung, pop an ubuntu 8.10 CD into the drive, boot to “repair a broken system” and then edit that file.