Guest user os X lion

Question

I am on vacation, out of the country, and I have been using my MacBook Pro (OS X Lion 10.7) without a problem. The other night I turned the computer off, but when I turned it on in the morning, I was only allowed to access my computer via Guest User. I have never seen this account before, I don't know its password, and so I could only log into it via the Safari item.
I know that this is a feature related to Find My Mac. For the record, on my friend's computer I tried using that to see if the Find My Mac option worked, and it did not. It said my computer was offline when it was not.
This seems to be what my problem is: https://discussions.apple.com/thread/4133452?start=0&tstart=0.
Like the user in the above link, none of those options worked for me.
I was asked to do this and I did: http://support.apple.com/kb/HT1379
Then I tried reinstalling OS X Lion, because when I logged inI had to reboot or restart it as if I had a new computer or software. Because I am in a country with extremely slow internet and with frequent electricity outages, that did not work. I woke up to find my computer on the Guest User account screen again.
The Apple help phone line people did not know what to do and could not help at all. They acted like they've never heard of this problem before, which seems unlikely given this: http://reviews.cnet.com/8301-13727_7-20119806-263/os-x-10.7.2-with-icloud-showin g-guest-user-account-at-log-in/.
Then a friend asked me to try this: http://discussions.apple.com/thread/3192110?start=15&tstart=0
I did, but after trying several versions of this in terminal, nothing worked. I could not find the plist to delte or the volume. It did not recognize any of the commands, likely because I was in terminal, but not in the admin account that has access to all files.
Yesterday, I went into Disk Unitilities to back up one other copy of my drive just in case.
But if anyone has any idea what I can do to solve this problem I would be most grateful.

Answer 1

http://9to5mac.com/2011/06/07/find-my-mac-detailed-in-latest-lion-preview/
It's there to "Find My Mac".