Update: Hot damn. It's working again, even if I seem to be in 2006. The problem is with my computer, but when I tried to update the clock (Windows 98, click on the time for clock/calendar changes), lj wouldn't let me post articles at all.
Since then, I've reverted my drive to an earlier date (which didn't seem to work), rebooted a number of times (which may have worked), and read the FAQ on how to post by email (which may have worked by Murphy magic).
Any advice on more sophisticated ways of getting my computer back to 2005 would be appreciated.