DEAR 10 ~ a similar thing happened to me too; I was lurking around here for a few months before I actually joined. When I signed up, I really didn't know how much I weighed either (cuz I didn't have any scales); so I put down the weight at my last weigh-in at the docs the year before (which was 307); but I now know that I actually weighed 312 + plus I had gained 8 lbs over the winter (Christmas season did me in); so I actually weighed 320 lbs.
That's essentially why I came here in the first place, becuz I knew I was slipping back into old, bad habits again. I was devastated when I saw the the real weight this spring when I got my new scales. I think that this happens to a lot of people. As much as I loathe the scales, they are a great reality check; I had no idea that I weighed in the 300's when I got weighed by the doc in late 2006. Later on, I found out my highest weight from the hospital from 1-2 years ago.
ANYWAYS, I felt embarrassed to change it, so now you have given me the nudge I needed to get at it. I have lost 2 lbs of that now, so I actually weigh 318 lbs; and I am desperately trying to get going again; hence the 10 lb mini-goal, below. I do have a problem also with water-weight fluctuations, as my legs swell each day (from 3-5 lbs), but I hope this will stop once I get down a little more.
Tuff as it is, I feel relieved about it all; so, thanx for your update!
ROSEBUD
Honesty and an update
I decided then and there that I was going to start weighing myself regularly so I would be more accountable and since I was cutting back on the alcohol and increasing my exercise I figured it would only go down. Well, today I got on that &*$@ thing again and I have gone down three pounds!!! 
Plus, I've got PMS symptoms so I'm thinking it's going to be down even more next time I get on. I've updated my ticker and I'm on my way!!!!!! Woo Freakin' Hoo!!! 
